Function TestGenerateParallelManyFiles

codegen/generator/generate_merge_test.go:78–131

TestGenerateParallelManyFiles verifies that parallel file writing correctly handles multiple files (more than runtime.NumCPU()) to exercise the worker pool distribution. This ensures all workers process files and all files are written correctly.

(t *testing.T)

// pool distribution. This ensures all workers process files and all files are
// written correctly.
func TestGenerateParallelManyFiles(t *testing.T) {
	t.Cleanup(func() { Generators = generators })

	// Generate 20 files to ensure we exceed typical CPU counts and exercise
	// the worker pool's work distribution.
	const numFiles = 20
	Generators = func(cmd string) ([]Genfunc, error) {
		return []Genfunc{
			func(genpkg string, roots []eval.Root) ([]*codegen.File, error) {
				files := make([]*codegen.File, numFiles)
				for i := 0; i < numFiles; i++ {
					f := &codegen.File{
						Path: filepath.Join(codegen.Gendir, "types", filepath.Join("parallel", filepath.Join("file"+string(rune('a'+i%26)), "test"+string(rune('0'+i/26))+".go"))),
					}
					f.SectionTemplates = []*codegen.SectionTemplate{
						codegen.Header("Types", "types", nil),
						{
							Name:   "type-def",
							Source: "type Test" + string(rune('A'+i)) + " struct{ ID int }\n",
						},
					}
					files[i] = f
				}
				return files, nil
			},
		}, nil
	}

	dir := t.TempDir()
	outputs, err := Generate(dir, "gen", false)
	if err != nil {
		t.Fatalf("Generate failed: %v", err)
	}
	outputs = assertVersionFile(t, dir, outputs)

	// Verify all generator files were written
	if len(outputs) != numFiles {
		t.Fatalf("expected %d output files, got %d", numFiles, len(outputs))
	}

	// Verify each file exists and has correct content
	for i := 0; i < numFiles; i++ {
		outpath := filepath.Join(dir, codegen.Gendir, "types", filepath.Join("parallel", filepath.Join("file"+string(rune('a'+i%26)), "test"+string(rune('0'+i/26))+".go")))
		bs, err := os.ReadFile(outpath)
		if err != nil {
			t.Fatalf("failed reading file %d: %v", i, err)
		}
		content := string(bs)
		expected := "type Test" + string(rune('A'+i)) + " struct"
		if !strings.Contains(content, expected) {
			t.Fatalf("file %d missing expected content %q:\n%s", i, expected, content)
		}
	}
}

// TestGenerateParallelWithMerge verifies that parallel file writing correctly
// handles file merging when multiple generators target the same path. This