Implement testing.TB.Context, added in go 1.24

fake_coverage_test.go

@@ -36,10 +36,6 @@ func TestTBCoverage(t *testing.T) {
 		}
 
 		mn := m.Name
-		// TODO(prashant): Implement new methods added in 1.24 before release.
-		if mn == "Context" {
-			continue
-		}
 		if _, ok := ftSet[mn]; !ok {
 			t.Errorf("faket missing testing.TB.%s", mn)
 		}

fake_tb.go

@@ -1,6 +1,7 @@
 package faket
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -19,6 +20,9 @@ type fakeTB struct {
 	// Since this is an interface, unimplemented methods will panic.
 	testing.TB
 
+	ctx       context.Context
+	cancelCtx context.CancelFunc
+
 	mu sync.Mutex // protects all of the below fields.
 
 	cleanups []cleanup
@@ -68,7 +72,10 @@ func RunTest(testFn func(t testing.TB)) TestResult {
 }
 
 func newFakeTB() *fakeTB {
+	ctx, cancel := context.WithCancel(context.Background())
 	return &fakeTB{
+		ctx:       ctx,
+		cancelCtx: cancel,
 		completed: make(chan struct{}),
 		helpers:   make(map[uintptr]struct{}),
 	}
@@ -105,6 +112,8 @@ func (tb *fakeTB) checkPanic() {
 }
 
 func (tb *fakeTB) runCleanups() {
+	tb.cancelCtx()
+
 	// Set cleanupRoot so log callers can use cleanup's callers.
 	if self := getCaller(withSelf); self != 0 {
 		f := pcToFunction(self)
@@ -450,3 +459,7 @@ func (tb *fakeTB) Chdir(dir string) {
 		}
 	})
 }
+
+func (tb *fakeTB) Context() context.Context {
+	return tb.ctx
+}

integration_1_24_test.go

@@ -19,7 +19,7 @@ func TestCmp_Chdir(t *testing.T) {
 		opts := cmptest.Opts{
 			LogReplace: func(s string) string {
 				s = regexp.MustCompile("testing.go:[0-9]+").ReplaceAllString(s, "testing.go:Chdir")
-				s = strings.ReplaceAll(s, "fake_tb.go:428", "testing.go:Chdir")
+				s = regexp.MustCompile("fake_tb.go:[0-9]+").ReplaceAllString(s, "testing.go:Chdir")
 				return s
 			},
 		}
@@ -58,3 +58,17 @@ func TestCmp_Chdir(t *testing.T) {
 	want.Equal(t, "Getwd", postWD, initialWD)
 	want.Equal(t, "PWD", postPWD, initialPWD)
 }
+
+func TestCmp_Context(t *testing.T) {
+	cmptest.Compare(t, func(t testing.TB) {
+		ctx := t.Context()
+		t.Log("no ctx.Err initially", ctx.Err())
+
+		deadline, ok := ctx.Deadline()
+		t.Log("ctx has no deadline", ok, deadline)
+
+		t.Cleanup(func() {
+			t.Log("but err in cleanup", ctx.Err())
+		})
+	})
+}

testdata/cmp_test_results.json

@@ -14,6 +14,13 @@
 {"Time":"2022-06-11T00:00:00.0Z","Action":"output","Package":"github.com/prashantv/faket","Test":"TestCmp_Chdir/success","Output":"    --- PASS: TestCmp_Chdir/success (0.01s)\n"}
 {"Time":"2022-06-11T00:00:00.0Z","Action":"pass","Package":"github.com/prashantv/faket","Test":"TestCmp_Chdir/success","Elapsed":0}
 {"Time":"2022-06-11T00:00:00.0Z","Action":"fail","Package":"github.com/prashantv/faket","Test":"TestCmp_Chdir","Elapsed":0}
+{"Time":"2022-06-11T00:00:00.0Z","Action":"run","Package":"github.com/prashantv/faket","Test":"TestCmp_Context"}
+{"Time":"2022-06-11T00:00:00.0Z","Action":"output","Package":"github.com/prashantv/faket","Test":"TestCmp_Context","Output":"=== RUN   TestCmp_Context\n"}
+{"Time":"2022-06-11T00:00:00.0Z","Action":"output","Package":"github.com/prashantv/faket","Test":"TestCmp_Context","Output":"    integration_1_24_test.go:65: no ctx.Err initially \u003cnil\u003e\n"}
+{"Time":"2022-06-11T00:00:00.0Z","Action":"output","Package":"github.com/prashantv/faket","Test":"TestCmp_Context","Output":"    integration_1_24_test.go:68: ctx has no deadline false 0001-01-01 00:00:00 +0000 UTC\n"}
+{"Time":"2022-06-11T00:00:00.0Z","Action":"output","Package":"github.com/prashantv/faket","Test":"TestCmp_Context","Output":"    integration_1_24_test.go:71: but err in cleanup context canceled\n"}
+{"Time":"2022-06-11T00:00:00.0Z","Action":"output","Package":"github.com/prashantv/faket","Test":"TestCmp_Context","Output":"--- PASS: TestCmp_Context (0.01s)\n"}
+{"Time":"2022-06-11T00:00:00.0Z","Action":"pass","Package":"github.com/prashantv/faket","Test":"TestCmp_Context","Elapsed":0}
 {"Time":"2022-06-11T00:00:00.0Z","Action":"run","Package":"github.com/prashantv/faket","Test":"TestCmp_Success"}
 {"Time":"2022-06-11T00:00:00.0Z","Action":"output","Package":"github.com/prashantv/faket","Test":"TestCmp_Success","Output":"=== RUN   TestCmp_Success\n"}
 {"Time":"2022-06-11T00:00:00.0Z","Action":"output","Package":"github.com/prashantv/faket","Test":"TestCmp_Success","Output":"    integration_test.go:20: log1\n"}