Share immutable in-memory filesystems

internal/framework/promptfs/prompt_fs_test.go

@@ -103,6 +103,70 @@ func TestModulePromptFSRejectsNestedSharedFileName(t *testing.T) {
 	}
 }
 
+func TestModulePromptFSRejectsDuplicateNormalizedDestinations(t *testing.T) {
+	for _, test := range []struct {
+		name string
+		call func() error
+		want string
+	}{
+		{
+			name: "module",
+			call: func() error {
+				_, err := ModulePromptFS("module.test", fstest.MapFS{
+					"assets/prompts/first.md":  {Data: []byte("first")},
+					"assets/prompts/second.md": {Data: []byte("second")},
+				}, []ModulePromptFile{
+					{Name: "task.md", Path: "assets/prompts/first.md"},
+					{Name: " task.md ", Path: "assets/prompts/second.md"},
+				})
+				return err
+			},
+			want: `duplicate module prompt destination "assets/prompts/module.test/task.md"`,
+		},
+		{
+			name: "sharedassets",
+			call: func() error {
+				shared := fstest.MapFS{
+					"shared/first.md":  {Data: []byte("first")},
+					"shared/second.md": {Data: []byte("second")},
+				}
+				_, err := ModulePromptFS("module.test", fstest.MapFS{}, nil,
+					SharedPromptFile{Name: "task.md", FS: shared, Path: "shared/first.md"},
+					SharedPromptFile{Name: " task.md ", FS: shared, Path: "shared/second.md"},
+				)
+				return err
+			},
+			want: `duplicate sharedassets prompt destination "assets/prompts/module.test/sharedassets/task.md"`,
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			if err := test.call(); err == nil || err.Error() != test.want {
+				t.Fatalf("ModulePromptFS() error = %v, want %q", err, test.want)
+			}
+		})
+	}
+}
+
+func TestModulePromptFSAllowsMatchingModuleAndSharedBasenames(t *testing.T) {
+	fsys, err := ModulePromptFS("module.test", fstest.MapFS{
+		"assets/prompts/system.md": {Data: []byte("module")},
+	}, []ModulePromptFile{{Name: "system.md", Path: "assets/prompts/system.md"}},
+		SharedPromptFile{Name: "system.md", FS: fstest.MapFS{"shared/system.md": {Data: []byte("shared")}}, Path: "shared/system.md"},
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for name, want := range map[string]string{
+		"assets/prompts/module.test/system.md":              "module",
+		"assets/prompts/module.test/sharedassets/system.md": "shared",
+	} {
+		data, err := fs.ReadFile(fsys, name)
+		if err != nil || string(data) != want {
+			t.Fatalf("ReadFile(%q) = %q, %v; want %q", name, data, err, want)
+		}
+	}
+}
+
 func TestModulePromptFSRejectsInvalidModuleDir(t *testing.T) {
 	_, err := ModulePromptFS(".", fstest.MapFS{}, nil)
 	if err == nil || !strings.Contains(err.Error(), "module prompt directory") {