diff --git a/LICENSE.md b/LICENSE.md
index e34262b5..525b7116 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -1,4 +1,4 @@
-Copyright (c) 2025, [CyberDojo Foundation](http://blog.cyber-dojo.org/2015/08/cyber-dojo-foundation.html)
+Copyright (c) 2026, [CyberDojo Foundation](http://blog.cyber-dojo.org/2015/08/cyber-dojo-foundation.html)
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
diff --git a/README.md b/README.md
index 7dfb2d43..d50194f2 100644
--- a/README.md
+++ b/README.md
@@ -20,9 +20,7 @@ $ make {image_server|image_client}
 # Run all tests
 $ make {test_server|test_client}
 
-# Run only specific tests
-$ ./bin/run_tests.sh {-h|--help}
-$ ./bin/run_tests.sh {server|client} B56Sp3
+# Run only tests whose id starts with B56
 $ make {test_server|test_client} tid=B56
 
 # Check test metrics
diff --git a/test/client/differ_client_test.rb b/test/client/differ_client_test.rb
index 5f712532..73da0aae 100755
--- a/test/client/differ_client_test.rb
+++ b/test/client/differ_client_test.rb
@@ -4,19 +4,16 @@
 require 'cgi'
 
 class DifferClientTest < ClientTestBase
-  def self.id58_prefix
-    '2q0'
-  end
 
   hostname = 'server'
   port = ENV['CYBER_DOJO_DIFFER_PORT'].to_i
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'jj8', %w[
-    clients use probes with a trailing question mark in their path which is overly cute
-    so support both with and without ? until all clients have switched to non ?
-  ] do
+  test '2q0jj8', %w(
+  | clients use probes with a trailing question mark in their path which is overly cute
+  | so support both with and without ? until all clients have switched to non ?
+  ) do
     requester = HttpJsonHash::Requester.new(hostname, port)
     http = HttpJsonHash::Unpacker.new('differ', requester)
     assert http.get('alive?', {}).instance_of?(TrueClass)
@@ -25,10 +22,10 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'jj9', %w(
-    /diff_summary can use GET query args
-    which is important since in jQuery a $.getJSON() call
-    always passes its arguments in the query string
+  test '2q0jj9', %w(
+  | /diff_summary can use GET query args
+  | which is important since in jQuery a $.getJSON() call
+  | always passes its arguments in the query string
   ) do
     requester = HttpJsonHash::Requester.new(hostname, port)
     http = HttpJsonHash::Unpacker.new('differ', requester)
@@ -73,16 +70,18 @@ def self.id58_prefix
   # >10K query was a problem for thin at one time
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '347',
-       '>10K query is not rejected by web server' do
+  test '2q0347', %w(
+  | >10K query is not rejected by web server
+  ) do
     @old_files = { 'wibble.h' => 'X' * 45 * 1024 }
     @new_files = {}
     id, was_index, now_index = *run_diff_prepare
     differ.diff_summary(id, was_index, now_index)
   end
 
-  test '348',
-       '>10K query in nested sub-dir is not rejected by web-server' do
+  test '2q0348', %w(
+  | >10K query in nested sub-dir is not rejected by web-server
+  ) do
     @old_files = { 'gh/jk/wibble.h' => 'X' * 45 * 1024 }
     @new_files = {}
     id, was_index, now_index = *run_diff_prepare
@@ -91,12 +90,16 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '944', 'probes 200' do
+  test '2q0944', %w(
+  | probes 200
+  ) do
     assert differ.alive.instance_of?(TrueClass)
     assert differ.ready.instance_of?(TrueClass)
   end
 
-  test '945', 'sha 200' do
+  test '2q0945', %w(
+  | sha 200
+  ) do
     sha = differ.sha
     assert_equal 40, sha.size, 'sha.size'
     sha.each_char do |ch|
@@ -108,7 +111,9 @@ def self.id58_prefix
   # failure cases
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '7C0', %w[calling unknown method raises] do
+  test '2q07C0', %w(
+  | calling unknown method raises
+  ) do
     requester = HttpJsonHash::Requester.new(hostname, port)
     http = HttpJsonHash::Unpacker.new('differ', requester)
     error = assert_raises(RuntimeError) { http.get(:shar, { x: 42 }) }
@@ -131,8 +136,9 @@ def self.id58_prefix
   # delete file
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '313',
-       'deleted empty file' do
+  test '2q0313', %w(
+  | deleted empty file
+  ) do
     @old_files = { 'hiker.h' => '' }
     @new_files = {}
     assert_diff(
@@ -158,8 +164,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '314',
-       'deleted empty file in nested sub-dir' do
+  test '2q0314', %w(
+  | deleted empty file in nested sub-dir
+  ) do
     @old_files = { '6/7/8/hiker.h' => '' }
     @new_files = {}
     assert_diff(
@@ -175,8 +182,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'FE9',
-       'deleted non-empty file shows as all lines deleted' do
+  test '2q0FE9', %w(
+  | deleted non-empty file shows as all lines deleted
+  ) do
     @old_files = { 'hiker.h' => "a\nb\nc\nd\n" }
     @new_files = {}
     assert_diff(
@@ -208,8 +216,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'FEA',
-       'deleted non-empty file in nested sub-dir shows as all lines deleted' do
+  test '2q0FEA', %w(
+  | deleted non-empty file in nested sub-dir shows as all lines deleted
+  ) do
     @old_files = { '4/5/6/7/hiker.h' => "a\nb\nc\nd\n" }
     @new_files = {}
     assert_diff(
@@ -233,9 +242,10 @@ def self.id58_prefix
   # delete content
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'B67',
-       'all lines deleted but file not deleted',
-       'shows as all lines deleted' do
+  test '2q0B67', %w(
+  | all lines deleted but file not deleted
+  | shows as all lines deleted
+  ) do
     @old_files = { 'hiker.h' => "a\nb\nc\nd\n" }
     @new_files = { 'hiker.h' => '' }
     assert_diff(
@@ -257,9 +267,10 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'B68',
-       'all lines deleted but nested sub-dir file not deleted',
-       'shows as all lines deleted' do
+  test '2q0B68', %w(
+  | all lines deleted but nested sub-dir file not deleted
+  | shows as all lines deleted
+  ) do
     @old_files = { 'r/t/y/hiker.h' => "a\nb\nc\nd\n" }
     @new_files = { 'r/t/y/hiker.h' => '' }
     assert_diff(
@@ -283,8 +294,9 @@ def self.id58_prefix
   # new file
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '95F',
-       %w[created new empty file] do
+  test '2q095F', %w(
+  | created new empty file
+  ) do
     @old_files = {}
     @new_files = { 'diamond.h' => '' }
     assert_diff(
@@ -300,8 +312,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '960',
-       %w[created empty file in nested sub-dir] do
+  test '2q0960', %w(
+  | created empty file in nested sub-dir
+  ) do
     @old_files = {}
     @new_files = { 'a/b/c/diamond.h' => '' }
     assert_diff(
@@ -327,8 +340,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '2C3',
-       %w[created non-empty file] do
+  test '2q02C3', %w(
+  | created non-empty file
+  ) do
     @old_files = {}
     @new_files = { 'diamond.h' => "a\nb\nc\nd" }
     assert_diff(
@@ -350,8 +364,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '2C4',
-       %w[created non-empty file in nested sub-dir] do
+  test '2q02C4', %w(
+  | created non-empty file in nested sub-dir
+  ) do
     @old_files = {}
     @new_files = { 'q/w/e/diamond.h' => "a\nb\nc\nd" }
     assert_diff(
@@ -375,8 +390,9 @@ def self.id58_prefix
   # change
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'E3E',
-       %w[changed non-empty file] do
+  test '2q0E3E', %w(
+  | changed non-empty file
+  ) do
     @old_files = { 'diamond.h' => 'a' }
     @new_files = { 'diamond.h' => 'b' }
     assert_diff(
@@ -396,8 +412,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'E3F',
-       %w[changed non-empty file in nested sub-dir] do
+  test '2q0E3F', %w(
+  | changed non-empty file in nested sub-dir
+  ) do
     @old_files = { 't/y/u/diamond.h' => 'a1' }
     @new_files = { 't/y/u/diamond.h' => 'b2' }
     assert_diff(
@@ -417,9 +434,10 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'B9E',
-       'changed non-empty file shows as deleted and added lines',
-       'with each hunk in its own indexed section' do
+  test '2q0B9E', %w(
+  | changed non-empty file shows as deleted and added lines
+  | with each hunk in its own indexed section
+  ) do
     @old_files = {
       'diamond.h' =>
         [
@@ -475,9 +493,10 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'B9F',
-       'changed non-empty file in nested sub-dir shows as deleted and added lines',
-       'with each hunk in its own indexed section' do
+  test '2q0B9F', %w(
+  | changed non-empty file in nested sub-dir shows as deleted and added lines
+  | with each hunk in its own indexed section
+  ) do
     @old_files = {
       'a/b/c/diamond.h' =>
         [
@@ -535,8 +554,9 @@ def self.id58_prefix
   # renamed file
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'E50',
-       '100% identical renamed file' do
+  test '2q0E50', %w(
+  | 100% identical renamed file
+  ) do
     @old_files = { 'hiker.h'   => "a\nb\nc\nd" }
     @new_files = { 'diamond.h' => "a\nb\nc\nd" }
     assert_diff(
@@ -567,8 +587,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'E51',
-       '100% identical renamed file in nested sub-dir' do
+  test '2q0E51', %w(
+  | 100% identical renamed file in nested sub-dir
+  ) do
     @old_files = { 'a/f/d/hiker.h'   => "a\nb\nc\nd" }
     @new_files = { 'a/f/d/diamond.h' => "a\nb\nc\nd" }
     assert_diff(
@@ -589,8 +610,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'FDB',
-       '<100% identical rename' do
+  test '2q0FDB', %w(
+  | <100% identical rename
+  ) do
     @old_files = { 'hiker.h'   => "a\nb\nc\nd" }
     @new_files = { 'diamond.h' => "a\nb\nX\nd" }
     assert_diff(
@@ -613,8 +635,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'FDC',
-       '<100% identical renamed in nested sub-dir' do
+  test '2q0FDC', %w(
+  | <100% identical renamed in nested sub-dir
+  ) do
     @old_files = { 'a/b/c/hiker.h'   => "a\nb\nc\nd" }
     @new_files = { 'a/b/c/diamond.h' => "a\nb\nX\nd" }
     assert_diff(
@@ -639,8 +662,9 @@ def self.id58_prefix
   # unchanged files
   # - - - - - - - - - - - - - - - - - - - -
 
-  test 'AEC',
-       'unchanged empty files' do
+  test '2q0AEC', %w(
+  | unchanged empty files
+  ) do
     @old_files = { 'diamond.h' => '' }
     @new_files = { 'diamond.h' => '' }
     assert_diff(
@@ -656,8 +680,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '7FF',
-       'unchanged empty-file in nested sub-dir' do
+  test '2q07FF', %w(
+  | unchanged empty-file in nested sub-dir
+  ) do
     @old_files = { 'w/e/r/diamond.h' => '' }
     @new_files = { 'w/e/r/diamond.h' => '' }
     assert_diff(
@@ -673,8 +698,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '365',
-       'unchanged non-empty file' do
+  test '2q0365', %w(
+  | unchanged non-empty file
+  ) do
     @old_files = { 'diamond.h' => "a\nb\nc\nd" }
     @new_files = { 'diamond.h' => "a\nb\nc\nd" }
     assert_diff(
@@ -695,8 +721,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - -
 
-  test '366',
-       'unchanged non-empty file in nested sub-dir shows as all lines same' do
+  test '2q0366', %w(
+  | unchanged non-empty file in nested sub-dir shows as all lines same
+  ) do
     @old_files = { 'r/t/y/diamond.h' => "a\nbb\nc\nd" }
     @new_files = { 'r/t/y/diamond.h' => "a\nbb\nc\nd" }
     assert_diff(
@@ -825,4 +852,5 @@ def line(text, type, number)
   def section(index)
     { 'type' => 'section', 'index' => index }
   end
+
 end
diff --git a/test/client/http_response_unpacker_test.rb b/test/client/http_response_unpacker_test.rb
index 4344c174..61aee832 100644
--- a/test/client/http_response_unpacker_test.rb
+++ b/test/client/http_response_unpacker_test.rb
@@ -5,11 +5,6 @@
 require 'ostruct'
 
 class HttpResponseUnpackerTest < ClientTestBase
-  def self.id58_prefix
-    'C20'
-  end
-
-  # - - - - - - - - - - - - - - - - -
 
   class HttpJsonRequestBodyStubber
     def initialize(body)
@@ -21,11 +16,11 @@ def get(_path, _args, _params = {})
     end
   end
 
-  test 'QN3', %w(
-    |when an http-proxy
-    |receives a JSON-Hash in its response.body
-    |which has a key matching the query-string (without the args)
-    |then it returns the value for that key in the JSON-Hash
+  test 'C20QN3', %w(
+  | when an http-proxy
+  | receives a JSON-Hash in its response.body
+  | which has a key matching the query-string (without the args)
+  | then it returns the value for that key in the JSON-Hash
   ) do
     unpacker = stub('{"diff_summary":42}')
     diff_summary = unpacker.get('diff_summary', {})
@@ -34,42 +29,42 @@ def get(_path, _args, _params = {})
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'QN4', %w[
-    |when an http-proxy
-    |receives non-JSON in its response.body
-    |it raises an exception
-  ] do
+  test 'C20QN4', %w(
+  | when an http-proxy
+  | receives non-JSON in its response.body
+  | it raises an exception
+  ) do
     raises_exception('xxxx', 'body is not JSON')
   end
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'QN5', %w(
-    |when an http-proxy
-    |receives JSON (but not a Hash) in its response.body
-    |it raises an exception
+  test 'C20QN5', %w(
+  | when an http-proxy
+  | receives JSON (but not a Hash) in its response.body
+  | it raises an exception
   ) do
     raises_exception('[]', 'body is not JSON Hash')
   end
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'QN6', %w[
-    |when an http-proxy
-    |receives JSON-Hash with an exception key in its response.body
-    |it raises an exeption
-  ] do
+  test 'C20QN6', %w(
+  | when an http-proxy
+  | receives JSON-Hash with an exception key in its response.body
+  | it raises an exeption
+  ) do
     raises_exception('{"exception":42}', 'body has embedded exception')
   end
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'QN7', %w[
-    |when an http-proxy
-    |receives JSON-Hash in its response.body
-    |which does not contain the requested method's key
-    |it raises an exeption
-  ] do
+  test 'C20QN7', %w(
+  | when an http-proxy
+  | receives JSON-Hash in its response.body
+  | which does not contain the requested method's key
+  | it raises an exeption
+  ) do
     raises_exception('{"wibble":42}', 'body is missing diff_summary key')
   end
 
@@ -88,4 +83,5 @@ def raises_exception(body_stub, expected_message)
     json = JSON.parse(error.message)
     assert_equal expected_message, json['message']
   end
+
 end
diff --git a/test/client/lib/coverage_metrics_limits.rb b/test/client/lib/coverage_metrics_limits.rb
index e095cd3a..213464d3 100644
--- a/test/client/lib/coverage_metrics_limits.rb
+++ b/test/client/lib/coverage_metrics_limits.rb
@@ -3,7 +3,7 @@
 def metrics
   [
     [ nil ],
-    [ 'test.lines.total'    , '<=', 234 ],
+    [ 'test.lines.total'    , '<=', 230 ],
     [ 'test.lines.missed'   , '<=', 0   ],
     [ 'test.branches.total' , '<=', 0   ],
     [ 'test.branches.missed', '<=', 0   ],
diff --git a/test/client/lib/id58_test_base.rb b/test/client/lib/id58_test_base.rb
index 49335e9e..eda9cce5 100644
--- a/test/client/lib/id58_test_base.rb
+++ b/test/client/lib/id58_test_base.rb
@@ -27,11 +27,11 @@ def initialize(arg)
   @@seen_ids = []
   @@timings = {}
 
-  def self.test(id58_suffix, *lines, &test_block)
+  def self.test(id58, *lines, &test_block)
     src = test_block.source_location
     src_file = File.basename(src[0])
     src_line = src[1].to_s
-    id58 = checked_id58(id58_suffix, lines)
+    id58 = checked_id58(id58, lines)
     return unless @@args == [] || @@args.any? { |arg| id58.include?(arg) }
 
     name58 = lines.join(' ')
@@ -50,7 +50,7 @@ def self.test(id58_suffix, *lines, &test_block)
         id58_teardown
       end
     }
-    name = "id58 '#{id58_suffix}',\n'#{name58}'"
+    name = "id58 '#{id58}',\n'#{name58}'"
     define_method("test_\n#{name}".to_sym, &execute_around)
   end
 
@@ -78,25 +78,15 @@ def self.id58?(arg)
       arg.chars.all? { |chr| ID58_ALPHABET.include?(chr) }
   end
 
-  def self.checked_id58(id58_suffix, lines)
-    method = 'def self.id58_prefix'
-    pointer = "#{' ' * method.index('.')}!"
-    pointee = ['', pointer, method, '', ''].join("\n")
-    pointer = "\n\n#{pointer}"
-    raise "#{pointer}missing#{pointee}" unless respond_to?(:id58_prefix)
-    raise "#{pointer}empty#{pointee}" if id58_prefix == ''
-    raise "#{pointer}not id58#{pointee}" unless id58?(id58_prefix)
-
-    method = "test '#{id58_suffix}',"
+  def self.checked_id58(id58, lines)
+    method = "test '#{id58}',"
     pointer = "#{' ' * method.index("'")}!"
     proposition = lines.join(' ')
     pointee = ['', pointer, method, "'#{proposition}'", '', ''].join("\n")
-    id58 = id58_prefix + id58_suffix
     pointer = "\n\n#{pointer}"
-    raise "#{pointer}empty#{pointee}" if id58_suffix == ''
-    raise "#{pointer}not id58#{pointee}" unless id58?(id58_suffix)
+    raise "#{pointer}empty#{pointee}" if id58 == ''
+    raise "#{pointer}not id58#{pointee}" unless id58?(id58)
     raise "#{pointer}duplicate#{pointee}" if @@seen_ids.include?(id58)
-    raise "#{pointer}overlap#{pointee}" if id58_prefix[-2..] == id58_suffix[0..1]
 
     @@seen_ids << id58
     id58
diff --git a/test/server/diff_summary_test.rb b/test/server/diff_summary_test.rb
index 3c2c9414..29880c57 100644
--- a/test/server/diff_summary_test.rb
+++ b/test/server/diff_summary_test.rb
@@ -3,14 +3,10 @@
 require_relative 'differ_test_base'
 
 class DiffSummaryTest < DifferTestBase
-  def self.id58_prefix
-    '4DE'
-  end
-
-  # - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'j12',
-       'created empty file' do
+  test '4DEj12', %w(
+  | created empty file
+  ) do
     assert_diff_summary('RNCzUr', 2, 3,
                         :created, nil, 'empty.file', 0, 0, 0,
                         :unchanged, 'test_hiker.sh', 'test_hiker.sh', 0, 0, 8,
@@ -22,8 +18,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - -
 
-  test 'j13',
-       'deleted empty file' do
+  test '4DEj13', %w(
+  | deleted empty file
+  ) do
     assert_diff_summary('RNCzUr', 3, 4,
                         :deleted, 'empty.file', nil, 0, 0, 0,
                         :unchanged, 'test_hiker.sh', 'test_hiker.sh', 0, 0, 8,
@@ -35,8 +32,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - -
 
-  test 'j14',
-       'renamed empty file' do
+  test '4DEj14', %w(
+  | renamed empty file
+  ) do
     assert_diff_summary('RNCzUr', 5, 6,
                         :renamed, 'empty.file', 'empty.file.rename', 0, 0, 0,
                         :unchanged, 'test_hiker.sh', 'test_hiker.sh', 0, 0, 8,
@@ -48,8 +46,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - -
 
-  test 'j15',
-       'empty file renamed 100% identical across dirs' do
+  test '4DEj15', %w(
+  | empty file renamed 100% identical across dirs
+  ) do
     assert_diff_summary('RNCzUr', 6, 7,
                         :renamed, 'empty.file.rename', 'sub_dir/empty.file.rename', 0, 0, 0,
                         :unchanged, 'test_hiker.sh', 'test_hiker.sh', 0, 0, 8,
@@ -61,8 +60,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - -
 
-  test 'j16',
-       'empty file has one lines added' do
+  test '4DEj16', %w(
+  | empty file has one lines added
+  ) do
     assert_diff_summary('RNCzUr', 7, 8,
                         :changed, 'sub_dir/empty.file.rename', 'sub_dir/empty.file.rename', 1, 0, 0,
                         :unchanged, 'test_hiker.sh', 'test_hiker.sh', 0, 0, 8,
@@ -74,8 +74,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'k15',
-       'non-empty file deleted' do
+  test '4DEk15', %w(
+  | non-empty file deleted
+  ) do
     assert_diff_summary('RNCzUr', 8, 9,
                         :deleted, 'readme.txt', nil, 0, 14, 0,
                         :unchanged, 'test_hiker.sh', 'test_hiker.sh', 0, 0, 8,
@@ -87,8 +88,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - -
 
-  test 'k16',
-       'non-empty file renamed 100% identical' do
+  test '4DEk16', %w(
+  | non-empty file renamed 100% identical
+  ) do
     assert_diff_summary('RNCzUr', 9, 10,
                         :renamed, 'bats_help.txt', 'bats_help.txt.rename', 0, 0, 3,
                         :unchanged, 'test_hiker.sh', 'test_hiker.sh', 0, 0, 8,
@@ -99,8 +101,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - -
 
-  test 'k17',
-       'non-empty file renamed <100% identical' do
+  test '4DEk17', %w(
+  | non-empty file renamed <100% identical
+  ) do
     assert_diff_summary('RNCzUr', 13, 14,
                         :changed, 'bats_help.txt', 'bats_help.txt', 1, 1, 19, # data error. No rename here.
                         :unchanged, 'test_hiker.sh', 'test_hiker.sh', 0, 0, 8,
@@ -111,8 +114,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - -
 
-  test 'k18',
-       'two non-empty files both edited' do
+  test '4DEk18', %w(
+  | two non-empty files both edited
+  ) do
     assert_diff_summary('RNCzUr', 1, 2,
                         :changed, 'hiker.sh', 'hiker.sh', 1, 1, 5,
                         :changed, 'readme.txt', 'readme.txt', 6, 3, 8,
@@ -137,4 +141,5 @@ def assert_diff_summary(id, was_index, now_index, *diffs)
   def diff_summary(id, was_index, now_index)
     differ.diff_summary(id: id, was_index: was_index, now_index: now_index)
   end
+
 end
diff --git a/test/server/differ_test.rb b/test/server/differ_test.rb
index cb5228a4..186cfd69 100644
--- a/test/server/differ_test.rb
+++ b/test/server/differ_test.rb
@@ -3,9 +3,6 @@
 require_relative 'differ_test_base'
 
 class DifferTest < DifferTestBase
-  def self.id58_prefix
-    'C9s'
-  end
 
   def self.versions_test(id58_suffix, *lines, &block)
     versions = 0..2
@@ -26,7 +23,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
   # empty file
   # - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'A2C', 'empty file is created' do
+  versions_test 'C9sA2C', %w(
+  | empty file is created
+  ) do
     # Saver v2 uses git and its implementation currently relies on there
     # always being at least one file (cyber-dojo.sh cannot be deleted )
     @was_files = { 'xx' => 'Hello' }
@@ -40,7 +39,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'A5C', 'empty file is deleted' do
+  versions_test 'C9sA5C', %w(
+  | empty file is deleted
+  ) do
     @was_files = { 'empty.rb' => '' }
     @now_files = {}
     assert_diff [
@@ -51,7 +52,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test '3ED', 'empty file is unchanged' do
+  versions_test 'C9s3ED', %w(
+  | empty file is unchanged
+  ) do
     @was_files = { 'empty.py' => '' }
     @now_files = { 'empty.py' => '' }
     assert_diff [
@@ -62,7 +65,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'AA6', 'empty file is renamed 100% identical' do
+  versions_test 'C9sAA6', %w(
+  | empty file is renamed 100% identical
+  ) do
     @was_files = { 'plain' => '' }
     @now_files = { 'copy'  => '' }
     assert_diff [
@@ -73,7 +78,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'A2D', 'empty file is renamed 100% identical across dirs' do
+  versions_test 'C9sA2D', %w(
+  | empty file is renamed 100% identical across dirs
+  ) do
     @was_files = { 'plain'    => '' }
     @now_files = { 'a/b/copy' => '' }
     assert_diff [
@@ -84,7 +91,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'F2E', 'empty file has some content added' do
+  versions_test 'C9sF2E', %w(
+  | empty file has some content added
+  ) do
     @was_files = { 'empty.c' => '' }
     @now_files = { 'empty.c' => "three\nlines\nadded" }
     assert_diff [
@@ -102,7 +111,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
   # non-empty file
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'D09', 'non-empty file is created' do
+  versions_test 'C9sD09', %w(
+  | non-empty file is created
+  ) do
     # Saver v2 uses git and its implementation currently relies on there
     # always being at least one file (cyber-dojo.sh cannot be deleted )
     @was_files = { 'xx' => 'Hello' }
@@ -118,7 +129,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test '0C6', 'non-empty file is deleted' do
+  versions_test 'C9s0C6', %w(
+  | non-empty file is deleted
+  ) do
     @was_files = { 'non-empty.h' => "two\nlines" }
     @now_files = {}
     assert_diff [
@@ -133,7 +146,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test '21D', 'non-empty file is unchanged' do
+  versions_test 'C9s21D', %w(
+  | non-empty file is unchanged
+  ) do
     @was_files = { 'non-empty.h' => '#include<stdio.h>' }
     @now_files = { 'non-empty.h' => '#include<stdio.h>' }
     assert_diff [
@@ -146,7 +161,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'AA7', 'non-empty file is renamed 100% identical' do
+  versions_test 'C9sAA7', %w(
+  | non-empty file is renamed 100% identical
+  ) do
     @was_files = { 'plain' => 'xxx' }
     @now_files = { 'copy' => 'xxx' }
     assert_diff [
@@ -159,7 +176,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'BA7', 'non-empty file is renamed 100% identical across dirs' do
+  versions_test 'C9sBA7', %w(
+  | non-empty file is renamed 100% identical across dirs
+  ) do
     @was_files = { 'a/b/plain' => "a\nb\nc\nd" }
     @now_files = { 'copy' => "a\nb\nc\nd" }
     assert_diff [
@@ -175,7 +194,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'AA8', 'non-empty file is renamed <100% identical' do
+  versions_test 'C9sAA8', %w(
+  | non-empty file is renamed <100% identical
+  ) do
     @was_files = { 'hiker.h'   => "a\nb\nc\nd" }
     @now_files = { 'diamond.h' => "a\nb\nX\nd" }
     assert_diff [
@@ -193,7 +214,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test 'AA9', 'non-empty file is renamed <100% identical across dirs' do
+  versions_test 'C9sAA9', %w(
+  | non-empty file is renamed <100% identical across dirs
+  ) do
     @was_files = { '1/2/hiker.h'   => "a\nb\nc\nd" }
     @now_files = { '3/4/diamond.h' => "a\nb\nX\nd" }
     assert_diff [
@@ -211,7 +234,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test '4D0', 'non-empty file has some content added at the start' do
+  versions_test 'C9s4D0', %w(
+  | non-empty file has some content added at the start
+  ) do
     @was_files = { 'non-empty.c' => 'something' }
     @now_files = { 'non-empty.c' => "more\nsomething" }
     assert_diff [
@@ -226,7 +251,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test '4D1', 'non-empty file has some content added at the end' do
+  versions_test 'C9s4D1', %w(
+  | non-empty file has some content added at the end
+  ) do
     @was_files = { 'non-empty.c' => 'something' }
     @now_files = { 'non-empty.c' => "something\nmore" }
     assert_diff [
@@ -241,7 +268,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  versions_test '4D2', 'non-empty file has some content added in the middle' do
+  versions_test 'C9s4D2', %w(
+  | non-empty file has some content added in the middle
+  ) do
     @was_files = { 'non-empty.c' => "a\nc" }
     @now_files = { 'non-empty.c' => "a\nB\nc" }
     assert_diff [
@@ -257,7 +286,9 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  version_test 2, '4D3', 'diff-lines with a non-existent now-index raises reasonable exception' do
+  version_test 2, 'C9s4D3', %w(
+  | diff-lines with a non-existent now-index raises reasonable exception
+  ) do
     manifest = starter_manifest
     manifest['version'] = 2
     id = saver.kata_create(manifest)
@@ -392,4 +423,5 @@ def added(number, line)
   def one_line(type, number, line)
     { type: type, number: number, line: line }
   end
+
 end
diff --git a/test/server/external_disk_writer_test.rb b/test/server/external_disk_writer_test.rb
index a07a8364..20b39e4b 100755
--- a/test/server/external_disk_writer_test.rb
+++ b/test/server/external_disk_writer_test.rb
@@ -3,12 +3,10 @@
 require_relative 'differ_test_base'
 
 class ExternalDiskWriterTest < DifferTestBase
-  def self.id58_prefix
-    'FDF'
-  end
 
-  test 'D4C',
-       'what gets written gets read back' do
+  test 'FDFD4C', %w(
+  | what gets written gets read back
+  ) do
     Dir.mktmpdir('file_writer') do |tmp_dir|
       pathed_filename = "#{tmp_dir}/limerick.txt"
       content = 'the boy stood on the burning deck'
@@ -16,4 +14,5 @@ def self.id58_prefix
       File.open(pathed_filename, 'r') { |fd| assert_equal content, fd.read }
     end
   end
+
 end
diff --git a/test/server/external_gitter_test.rb b/test/server/external_gitter_test.rb
index eb71d7de..74804dbd 100755
--- a/test/server/external_gitter_test.rb
+++ b/test/server/external_gitter_test.rb
@@ -4,9 +4,6 @@
 require_relative 'spy_sheller'
 
 class ExternalGitterTest < DifferTestBase
-  def self.id58_prefix
-    'DC3'
-  end
 
   def id58_setup
     externals.instance_eval { @shell = SpySheller.new }
@@ -14,8 +11,9 @@ def id58_setup
 
   # - - - - - - - - - - - - - - - - -
 
-  test '0B4',
-       'git.setup' do
+  test 'DC30B4', %w(
+  | git.setup
+  ) do
     expected = [
       'git init --quiet',
       "git config user.name 'differ'",
@@ -27,8 +25,9 @@ def id58_setup
 
   # - - - - - - - - - - - - - - - - -
 
-  test '8AB',
-       'for git.add_commit_tag_0' do
+  test 'DC38AB', %w(
+  | for git.add_commit_tag_0
+  ) do
     expected = [
       'git add .',
       'git commit --allow-empty --all --message 0 --quiet',
@@ -38,8 +37,9 @@ def id58_setup
     assert_shell(expected)
   end
 
-  test '8AC',
-       'for git.add_commit_tag_1' do
+  test 'DC38AC', %w(
+  | for git.add_commit_tag_1
+  ) do
     expected = [
       'git add .',
       'git commit --allow-empty --all --message 1 --quiet',
@@ -51,8 +51,9 @@ def id58_setup
 
   # - - - - - - - - - - - - - - - - -
 
-  test '9A2',
-       'git.diff_0_1' do
+  test 'DC39A2', %w(
+  | git.diff_0_1
+  ) do
     expected = [
       'git diff',
       '--unified=99999999999',
@@ -77,4 +78,5 @@ def assert_shell(*messages)
   def path
     'a/b/c/'
   end
+
 end
diff --git a/test/server/external_sheller_test.rb b/test/server/external_sheller_test.rb
index 66d53dc3..50746071 100755
--- a/test/server/external_sheller_test.rb
+++ b/test/server/external_sheller_test.rb
@@ -3,26 +3,24 @@
 require_relative 'differ_test_base'
 
 class ExternalShellerTest < DifferTestBase
-  def self.id58_prefix
-    'C89'
-  end
-
-  # - - - - - - - - - - - - - - - - -
 
-  test 'DBB',
-       'assert_exec(*commands) returns stdout when the commands all succeed' do
+  test 'C89DBB', %w(
+  | assert_exec(*commands) returns stdout when the commands all succeed
+  ) do
     assert_equal 'Hello', shell.assert_exec('echo -n Hello')
   end
 
-  test '0B8',
-       'assert_cd_exec(path,*commands) returns stdout when the cd and the commands succeeds' do
+  test 'C890B8', %w(
+  | assert_cd_exec(path,*commands) returns stdout when the cd and the commands succeeds
+  ) do
     assert_equal 'Hello', shell.assert_cd_exec('.', 'echo -n Hello')
   end
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'AF6',
-       'assert_exec(*commands) raises when a command fails' do
+  test 'C89AF6', %w(
+  | assert_exec(*commands) raises when a command fails
+  ) do
     error = assert_raises { shell.assert_exec('zzzz') }
     json = JSON.parse(error.message)
     assert_equal '', json['stdout']
@@ -30,8 +28,9 @@ def self.id58_prefix
     assert_equal 127, json['exit_status']
   end
 
-  test 'ACD',
-       'assert_cd_exec(path,*commands) raises when the cd fails' do
+  test 'C89ACD', %w(
+  | assert_cd_exec(path,*commands) raises when the cd fails
+  ) do
     error = assert_raises { shell.assert_cd_exec('zzzz', 'echo -n Hello') }
     json = JSON.parse(error.message)
     assert_equal '', json['stdout']
@@ -40,12 +39,14 @@ def self.id58_prefix
     assert_equal 2, json['exit_status']
   end
 
-  test '995',
-       'assert_cd_exec(path,*commands) raises when a command fails' do
+  test 'C89995', %w(
+  | assert_cd_exec(path,*commands) raises when a command fails
+  ) do
     error = assert_raises { shell.assert_cd_exec('.', 'zzzz') }
     json = JSON.parse(error.message)
     assert_equal '', json['stdout']
     assert json['stderr'].end_with?("sh: zzzz: not found\n"), json['stderr']
     assert_equal 127, json['exit_status']
   end
+
 end
diff --git a/test/server/externals_test.rb b/test/server/externals_test.rb
index 1674ad05..b284713b 100755
--- a/test/server/externals_test.rb
+++ b/test/server/externals_test.rb
@@ -3,26 +3,27 @@
 require_relative 'differ_test_base'
 
 class ExternalsTest < DifferTestBase
-  def self.id58_prefix
-    '7A9'
-  end
 
-  test '920',
-       'default disk is ExternalDiskWriter' do
+  test '7A9920', %w(
+  | default disk is ExternalDiskWriter
+  ) do
     assert_equal External::DiskWriter, disk.class
   end
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'C8F',
-       'default git is ExternalGitter' do
+  test '7A9C8F', %w(
+  | default git is ExternalGitter
+  ) do
     assert_equal External::Gitter, git.class
   end
 
   # - - - - - - - - - - - - - - - - -
 
-  test '1B1',
-       'default shell is ExternalSheller' do
+  test '7A91B1', %w(
+  | default shell is ExternalSheller
+  ) do
     assert_equal External::Sheller, shell.class
   end
+
 end
diff --git a/test/server/git_diff_parse_filenames_test.rb b/test/server/git_diff_parse_filenames_test.rb
index 5fb933c6..e8a8fb4d 100644
--- a/test/server/git_diff_parse_filenames_test.rb
+++ b/test/server/git_diff_parse_filenames_test.rb
@@ -4,16 +4,14 @@
 require_app 'git_diff_parse_filenames'
 
 class GitDiffParseFilenamesTest < DifferTestBase
-  def self.id58_prefix
-    'wK7'
-  end
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
   # parse_old_new_filenames()
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'D5F',
-       'parse old & new filenames with space in both filenames' do
+  test 'wK7D5F', %w(
+  | parse old & new filenames with space in both filenames
+  ) do
     header = [
       'diff --git "e mpty.h" "e mpty.h"',
       'index 0000000..e69de29'
@@ -25,8 +23,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '1B5',
-       'parse old & new filenames with double-quote and space in both filenames' do
+  test 'wK71B5', %w(
+  | parse old & new filenames with double-quote and space in both filenames
+  ) do
     # double-quote " is a legal character in a linux filename
     header = [
       'diff --git "li n\"ux" "em bed\"ded"',
@@ -39,8 +38,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '50A',
-       'parse old & new filenames with double-quote and space only in new-filename' do
+  test 'wK750A', %w(
+  | parse old & new filenames with double-quote and space only in new-filename
+  ) do
     # git diff only double quotes filenames if it has to
     header = [
       'diff --git plain "em bed\"ded"',
@@ -53,8 +53,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '4D8',
-       'parse old & new filenames with double-quote and space only in old-filename' do
+  test 'wK74D8', %w(
+  | parse old & new filenames with double-quote and space only in old-filename
+  ) do
     # double-quote " is a legal character in a linux filename
     header = [
       'diff --git "emb ed\"ded" plain',
@@ -67,8 +68,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '740',
-       'new_filename is nil for for deleted file' do
+  test 'wK7740', %w(
+  | new_filename is nil for for deleted file
+  ) do
     header = [
       'diff --git Deleted.java Deleted.java',
       'deleted file mode 100644',
@@ -81,8 +83,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '2A9',
-       'old_filename is nil for new file' do
+  test 'wK72A9', %w(
+  | old_filename is nil for new file
+  ) do
     header = [
       'diff --git empty.h empty.h',
       'new file mode 100644',
@@ -95,8 +98,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'A90',
-       'parse old & new filenames for renamed file' do
+  test 'wK7A90', %w(
+  | parse old & new filenames for renamed file
+  ) do
     diff_lines = [
       'diff --git old_name.h "new \"name.h"',
       'similarity index 100%',
@@ -110,8 +114,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'AD7',
-       'parse old & new filenames for new file in nested sub-dir' do
+  test 'wK7AD7', %w(
+  | parse old & new filenames for new file in nested sub-dir
+  ) do
     header = [
       'diff --git 1/2/3/empty.h 1/2/3/empty.h',
       'new file mode 100644',
@@ -124,8 +129,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'AD8',
-       'parse old & new filenames for renamed file in nested sub-dir' do
+  test 'wK7AD8', %w(
+  | parse old & new filenames for renamed file in nested sub-dir
+  ) do
     diff_lines = [
       'diff --git 1/2/3/old_name.h 1/2/3/new_name.h',
       'similarity index 100%',
@@ -139,8 +145,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'AD9',
-       'parse old & new filenames for renamed file across nested sub-dir' do
+  test 'wK7AD9', %w(
+  | parse old & new filenames for renamed file across nested sub-dir
+  ) do
     diff_lines = [
       'diff --git 1/2/3/old_name.h 4/5/6/new_name.h',
       'similarity index 100%',
@@ -154,10 +161,10 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'AD0', %w[
-    parse old & new nested sub-dir filenames
-    with double-quote and space in both filenames
-  ] do
+  test 'wK7AD0', %w(
+  | parse old & new nested sub-dir filenames
+  | with double-quote and space in both filenames
+  ) do
     # double-quote " is a legal character in a linux filename
     header = [
       'diff --git "s/d/f/li n\"ux" "u/i/o/em bed\"ded"',
@@ -170,12 +177,12 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'AD1', %w[
-    parse old & new nested sub-dir filenames
-    with double-quote and space in both filenames
-    and where first sub-dir is a or b which could clash
-    with git-diff output which uses a/ and b/
-  ] do
+  test 'wK7AD1', %w(
+  | parse old & new nested sub-dir filenames
+  | with double-quote and space in both filenames
+  | and where first sub-dir is a or b which could clash
+  | with git-diff output which uses a/ and b/
+  ) do
     # double-quote " is a legal character in a linux filename
     header = [
       'diff --git "a/d/f/li n\"ux" "b/u/i/o/em bed\"ded"',
diff --git a/test/server/git_diff_parser_test.rb b/test/server/git_diff_parser_test.rb
index 109349ff..a52af258 100755
--- a/test/server/git_diff_parser_test.rb
+++ b/test/server/git_diff_parser_test.rb
@@ -3,14 +3,10 @@
 require_relative 'differ_test_base'
 
 class GitDiffParserTest < DifferTestBase
-  def self.id58_prefix
-    'B56'
-  end
-
-  # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'sP3',
-       'empty options in ctor gives no lines and no line_counts' do
+  test 'B56sP3', %w(
+  | empty options in ctor gives no lines and no line_counts
+  ) do
     diff = [
       'diff --git instructions instructions_new',
       'similarity index 87%',
@@ -50,8 +46,9 @@ def self.id58_prefix
   # parse_all
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'E10',
-       'parse diff containing filename with backslash' do
+  test 'B56E10', %w(
+  | parse diff containing filename with backslash
+  ) do
     diff = [
       'diff --git "\\\\was_newfile_FIU" "\\\\was_newfile_FIU"',
       'deleted file mode 100644',
@@ -82,8 +79,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '196',
-       'parse diff deleted file' do
+  test 'B56196', %w(
+  | parse diff deleted file
+  ) do
     diff = [
       'diff --git original original',
       'deleted file mode 100644',
@@ -106,8 +104,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '0FE',
-       'parse another diff-form of a deleted file' do
+  test 'B560FE', %w(
+  | parse another diff-form of a deleted file
+  ) do
     diff = [
       'diff --git untitled.rb untitled.rb',
       'deleted file mode 100644',
@@ -141,8 +140,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'D91',
-       'parse diff for renamed but unchanged file and newname is quoted' do
+  test 'B56D91', %w(
+  | parse diff for renamed but unchanged file and newname is quoted
+  ) do
     diff = [
       'diff --git "was_\\\\wa s_newfile_FIU" "\\\\was_newfile_FIU"',
       'similarity index 100%',
@@ -166,8 +166,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'E38',
-       'parse diff for renamed but unchanged file' do
+  test 'B56E38', %w(
+  | parse diff for renamed but unchanged file
+  ) do
     diff = [
       'diff --git oldname newname',
       'similarity index 100%',
@@ -191,8 +192,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'A61',
-       'parse diff for renamed and changed file' do
+  test 'B56A61', %w(
+  | parse diff for renamed and changed file
+  ) do
     diff = [
       'diff --git instructions instructions_new',
       'similarity index 87%',
@@ -244,8 +246,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '91D',
-       'parse diffs for two files' do
+  test 'B5691D', %w(
+  | parse diffs for two files
+  ) do
     diff = [
       'diff --git lines lines',
       'index 1d60b70..14fc1c2 100644',
@@ -302,8 +305,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '1BC',
-       'two hunks with no newline at end of file' do
+  test 'B561BC', %w(
+  | two hunks with no newline at end of file
+  ) do
     diff = [
       'diff --git lines lines',
       'index f70c2c0..ba0f878 100644',
@@ -342,8 +346,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'B2C',
-       'diff one-hunk one-line' do
+  test 'B56B2C', %w(
+  | diff one-hunk one-line
+  ) do
     diff = [
       'diff --git lines lines',
       'index 72943a1..f761ec1 100644',
@@ -372,8 +377,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test 'A8A',
-       'standard diff' do
+  test 'B56A8A', %w(
+  | standard diff
+  ) do
     diff = [
       'diff --git gapper.rb gapper.rb',
       'index 26bc41b..8a5b0b7 100644',
@@ -404,8 +410,9 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '3B5',
-       'find copies harder finds a rename' do
+  test 'B563B5', %w(
+  | find copies harder finds a rename
+  ) do
     diff = [
       'diff --git hiker.h diamond.h',
       'similarity index 99%',
@@ -420,11 +427,11 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  test '124', %w[
-    renamed but unchanged file has no trailing
-    --- or +++ lines and must not consume diff
-    of following file as its header_lines
-  ] do
+  test 'B56124', %w(
+  | renamed but unchanged file has no trailing
+  | --- or +++ lines and must not consume diff
+  |  of following file as its header_lines
+  ) do
     diff = [
       'diff --git hiker.h hiker.txt',
       'similarity index 100%',
@@ -475,4 +482,5 @@ def added(number, line)
   def src(type, number, line)
     { type: type, number: number, line: line }
   end
+
 end
diff --git a/test/server/http_proxy_response_test.rb b/test/server/http_proxy_response_test.rb
index 242488ce..c76af862 100644
--- a/test/server/http_proxy_response_test.rb
+++ b/test/server/http_proxy_response_test.rb
@@ -4,17 +4,12 @@
 require_relative 'http_adapter_stub'
 
 class HttpProxyResponseTest < DifferTestBase
-  def self.id58_prefix
-    'f28'
-  end
-
-  # - - - - - - - - - - - - - - - - -
 
-  test 'QN3', %w(
-    |when an http-proxy
-    |receives a JSON-Hash in its response.body
-    |which has a key matching the query-string (without the args)
-    |then it returns the value for that key in the JSON-Hash
+  test 'f28QN3', %w(
+  | when an http-proxy
+  | receives a JSON-Hash in its response.body
+  | which has a key matching the query-string (without the args)
+  | then it returns the value for that key in the JSON-Hash
   ) do
     externals.instance_exec { @saver_http = ::HttpAdapterStub.new('{"ready?":[42]}') }
     saver = ::External::Saver.new(externals)
@@ -23,21 +18,21 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'QN4', %w[
-    |when an http-proxy
-    |receives non-JSON in its response.body
-    |it raises an exception
-  ] do
+  test 'f28QN4', %w(
+  | when an http-proxy
+  | receives non-JSON in its response.body
+  | it raises an exception
+  ) do
     stub_saver_http('xxxx')
     ready_raises_exception('body is not JSON')
   end
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'QN5', %w(
-    |when an http-proxy
-    |receives JSON (but not a Hash) in its response.body
-    |it raises an exception
+  test 'f28QN5', %w(
+  | when an http-proxy
+  | receives JSON (but not a Hash) in its response.body
+  | it raises an exception
   ) do
     stub_saver_http('[]')
     ready_raises_exception('body is not JSON Hash')
@@ -45,23 +40,23 @@ def self.id58_prefix
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'QN6', %w[
-    |when an http-proxy
-    |receives JSON-Hash with an exception key in its response.body
-    |it raises an exception
-  ] do
+  test 'f28QN6', %w(
+  | when an http-proxy
+  | receives JSON-Hash with an exception key in its response.body
+  | it raises an exception
+  ) do
     stub_saver_http('{"exception":42}')
     ready_raises_exception('42')
   end
 
   # - - - - - - - - - - - - - - - - -
 
-  test 'QN7', %w[
-    |when an http-proxy
-    |receives JSON-Hash in its response.body
-    |which does not contain the requested method's key
-    |it raises an exception
-  ] do
+  test 'f28QN7', %w(
+  | when an http-proxy
+  | receives JSON-Hash in its response.body
+  | which does not contain the requested method's key
+  | it raises an exception
+  ) do
     stub_saver_http('{"wibble":42}')
     ready_raises_exception('body is missing ready? key')
   end
@@ -78,4 +73,5 @@ def ready_raises_exception(expected_message)
     error = assert_raises(HttpJsonHash::ServiceError) { prober.ready }
     assert_equal expected_message, error.message
   end
+
 end
diff --git a/test/server/lib/coverage_metrics_limits.rb b/test/server/lib/coverage_metrics_limits.rb
index 4a700d81..ed84f387 100644
--- a/test/server/lib/coverage_metrics_limits.rb
+++ b/test/server/lib/coverage_metrics_limits.rb
@@ -3,7 +3,7 @@
 def metrics
   [
     [ nil ],
-    [ 'test.lines.total'    , '<=', 545 ],
+    [ 'test.lines.total'    , '<=', 521 ],
     [ 'test.lines.missed'   , '<=', 0   ],
     [ 'test.branches.total' , '<=', 0   ],
     [ 'test.branches.missed', '<=', 0   ],
diff --git a/test/server/lib/id58_test_base.rb b/test/server/lib/id58_test_base.rb
index 48b9a4a4..1ef8a480 100644
--- a/test/server/lib/id58_test_base.rb
+++ b/test/server/lib/id58_test_base.rb
@@ -26,11 +26,11 @@ def initialize(arg)
   @@seen_ids = []
   @@timings = {}
 
-  def self.test(id58_suffix, *lines, &test_block)
+  def self.test(id58, *lines, &test_block)
     src = test_block.source_location
     src_file = File.basename(src[0])
     src_line = src[1].to_s
-    id58 = checked_id58(id58_suffix, lines)
+    id58 = checked_id58(id58, lines)
     return unless @@args == [] || @@args.any? { |arg| id58.include?(arg) }
 
     name58 = lines.join(' ')
@@ -49,7 +49,7 @@ def self.test(id58_suffix, *lines, &test_block)
         id58_teardown
       end
     }
-    name = "id58 '#{id58_suffix}',\n'#{name58}'"
+    name = "id58 '#{id58}',\n'#{name58}'"
     define_method("test_\n#{name}".to_sym, &execute_around)
   end
 
@@ -77,25 +77,15 @@ def self.id58?(arg)
       arg.chars.all? { |chr| ID58_ALPHABET.include?(chr) }
   end
 
-  def self.checked_id58(id58_suffix, lines)
-    method = 'def self.id58_prefix'
-    pointer = "#{' ' * method.index('.')}!"
-    pointee = ['', pointer, method, '', ''].join("\n")
-    pointer = "\n\n#{pointer}"
-    raise "#{pointer}missing#{pointee}" unless respond_to?(:id58_prefix)
-    raise "#{pointer}empty#{pointee}" if id58_prefix == ''
-    raise "#{pointer}not id58#{pointee}" unless id58?(id58_prefix)
-
-    method = "test '#{id58_suffix}',"
+  def self.checked_id58(id58, lines)
+    method = "test '#{id58}',"
     pointer = "#{' ' * method.index("'")}!"
     proposition = lines.join(' ')
     pointee = ['', pointer, method, "'#{proposition}'", '', ''].join("\n")
-    id58 = id58_prefix + id58_suffix
     pointer = "\n\n#{pointer}"
-    raise "#{pointer}empty#{pointee}" if id58_suffix == ''
-    raise "#{pointer}not id58#{pointee}" unless id58?(id58_suffix)
+    raise "#{pointer}empty#{pointee}" if id58 == ''
+    raise "#{pointer}not id58#{pointee}" unless id58?(id58)
     raise "#{pointer}duplicate#{pointee}" if @@seen_ids.include?(id58)
-    raise "#{pointer}overlap#{pointee}" if id58_prefix[-2..] == id58_suffix[0..1]
 
     @@seen_ids << id58
     id58
diff --git a/test/server/prober_test.rb b/test/server/prober_test.rb
index 4e4f3445..ead89ee0 100644
--- a/test/server/prober_test.rb
+++ b/test/server/prober_test.rb
@@ -4,19 +4,16 @@
 require 'ostruct'
 
 class ProberTest < DifferTestBase
-  def self.id58_prefix
-    '198'
-  end
 
-  test '601', %w[alive] do
+  test '198601', %w[alive] do
     assert true?(prober.alive)
   end
 
-  test '603', %w[ready] do
+  test '198603', %w[ready] do
     assert true?(prober.ready)
   end
 
-  test '604', %w[
+  test '198604', %w[
     |when saver http-proxy is not ready
     |then ready? is false
   ] do
@@ -24,7 +21,7 @@ def self.id58_prefix
     assert false?(prober.ready)
   end
 
-  test '191', %w[sha] do
+  test '198191', %w[sha] do
     sha = prober.sha
     assert_equal 40, sha.size
     sha.each_char do |ch|
@@ -41,4 +38,5 @@ def true?(arg)
   def false?(arg)
     arg.instance_of?(FalseClass)
   end
+
 end
diff --git a/test/server/utf8_clean_test.rb b/test/server/utf8_clean_test.rb
index 352e5cd2..26092e7d 100755
--- a/test/server/utf8_clean_test.rb
+++ b/test/server/utf8_clean_test.rb
@@ -4,15 +4,14 @@
 require_app 'utf8_clean'
 
 class Utf8CleanTest < DifferTestBase
-  def self.id58_prefix
-    '3D9'
-  end
 
-  test '7FE',
-       'cleaned string is not phased by invalid encodings' do
+  test '3D97FE', %w(
+  | cleaned string is not phased by invalid encodings
+  ) do
     bad_str = (100..1000).to_a.pack('c*').force_encoding('utf-8')
     refute bad_str.valid_encoding?
     good_str = Utf8.clean(bad_str)
     assert good_str.valid_encoding?
   end
+
 end