diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7be29be..a578baf 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,7 +6,7 @@ on:
       - main
   pull_request:
     branches:
-      - "*"
+      - '**'
 
 jobs:
   run-unit-tests:
diff --git a/actcache/cache_test.go b/actcache/cache_test.go
new file mode 100644
index 0000000..917e703
--- /dev/null
+++ b/actcache/cache_test.go
@@ -0,0 +1,134 @@
+// Copyright (c) 2025 Naren Yellavula & Cybrota contributors
+// Apache License, Version 2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+
+package actcache
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+// TestNewHashEntry ensures NewHashEntry returns an empty struct pointer.
+func TestNewHashEntry(t *testing.T) {
+	h := NewHashEntry()
+	if h == nil {
+		t.Fatalf("NewHashEntry() returned nil")
+	}
+	if h.SHA != "" || h.UpdatedAt != "" {
+		t.Errorf("expected empty hashEntry, got %+v", h)
+	}
+}
+
+// TestLoadCache_NoFile verifies that an absent cache.json results in an empty map.
+func TestLoadCache_NoFile(t *testing.T) {
+	dir := t.TempDir()
+	m, err := loadCache(dir)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(m) != 0 {
+		t.Errorf("expected empty map, got %v", m)
+	}
+}
+
+// TestLoadCache_InvalidJSON ensures invalid JSON surfaces an error.
+func TestLoadCache_InvalidJSON(t *testing.T) {
+	dir := t.TempDir()
+	os.WriteFile(filepath.Join(dir, "cache.json"), []byte("not-json"), 0o644)
+	if _, err := loadCache(dir); err == nil {
+		t.Fatal("expected error from invalid json, got nil")
+	}
+}
+
+// TestLoadCache_Valid verifies a valid cache.json is parsed correctly.
+func TestLoadCache_Valid(t *testing.T) {
+	dir := t.TempDir()
+	data := map[string]hashEntry{"a": {SHA: "1", UpdatedAt: time.Now().Format(time.RFC3339Nano)}}
+	b, _ := json.Marshal(data)
+	os.WriteFile(filepath.Join(dir, "cache.json"), b, 0o644)
+
+	m, err := loadCache(dir)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if m["a"].SHA != "1" {
+		t.Errorf("expected SHA '1', got %q", m["a"].SHA)
+	}
+}
+
+// TestSaveCache writes a map and confirms file contents.
+func TestSaveCache(t *testing.T) {
+	dir := t.TempDir()
+	data := map[string]hashEntry{"a": {SHA: "1", UpdatedAt: "time"}}
+	if err := saveCache(dir, data); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	b, err := os.ReadFile(filepath.Join(dir, "cache.json"))
+	if err != nil {
+		t.Fatalf("failed reading file: %v", err)
+	}
+	var out map[string]hashEntry
+	if err := json.Unmarshal(b, &out); err != nil {
+		t.Fatalf("invalid json written: %v", err)
+	}
+	if out["a"].SHA != "1" {
+		t.Errorf("expected sha '1', got %q", out["a"].SHA)
+	}
+}
+
+// TestGetCache simply proxies to loadCache.
+func TestGetCache(t *testing.T) {
+	dir := t.TempDir()
+	data := map[string]hashEntry{"x": {SHA: "abc"}}
+	b, _ := json.Marshal(data)
+	os.WriteFile(filepath.Join(dir, "cache.json"), b, 0o644)
+	m, err := GetCache(dir)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if m["x"].SHA != "abc" {
+		t.Errorf("expected sha 'abc', got %q", m["x"].SHA)
+	}
+}
+
+// TestUpdateCacheEntry adds or updates an entry and persists it.
+func TestUpdateCacheEntry(t *testing.T) {
+	dir := t.TempDir()
+	// start with an existing file
+	init := map[string]hashEntry{"y": {SHA: "old", UpdatedAt: ""}}
+	b, _ := json.Marshal(init)
+	os.WriteFile(filepath.Join(dir, "cache.json"), b, 0o644)
+
+	if err := UpdateCacheEntry(dir, "y", "newsha"); err != nil {
+		t.Fatalf("update failed: %v", err)
+	}
+
+	m, err := loadCache(dir)
+	if err != nil {
+		t.Fatalf("loadCache failed: %v", err)
+	}
+	if m["y"].SHA != "newsha" {
+		t.Errorf("expected sha 'newsha', got %q", m["y"].SHA)
+	}
+	if m["y"].UpdatedAt == "" {
+		t.Error("expected UpdatedAt to be set")
+	}
+}
+
+// TestCacheExists checks presence detection of cache.json.
+func TestCacheExists(t *testing.T) {
+	dir := t.TempDir()
+	if CacheExists(dir) {
+		t.Error("expected false when file missing")
+	}
+	os.WriteFile(filepath.Join(dir, "cache.json"), []byte("{}"), 0o644)
+	if !CacheExists(dir) {
+		t.Error("expected true when file exists")
+	}
+}