pkg/check

- optimized test-code for readability and small API surface
- native support for pkg.result

internal/greeter/greeter_test.go

@@ -4,9 +4,9 @@ import (
 	"testing"
 
 	"gitea.djmil.dev/go/template/internal/greeter"
+	"gitea.djmil.dev/go/template/pkg/check"
 	"gitea.djmil.dev/go/template/pkg/logger"
 	"gitea.djmil.dev/go/template/pkg/result"
-	"gitea.djmil.dev/go/template/pkg/testutil"
 )
 
 // ── Service (unit tests) ──────────────────────────────────────────────────────
@@ -16,12 +16,12 @@ func TestGreet(t *testing.T) {
 
 	t.Run("returns personalized greeting", func(t *testing.T) {
 		msg, err := svc.Greet("World").Unwrap()
-		testutil.NoError(t, err)
+		check.NoError(t, err)
-		testutil.Equal(t, msg, "Hello, World!")
+		check.Equal(t, msg, "Hello, World!")
 	})
 
 	t.Run("rejects empty name", func(t *testing.T) {
-		testutil.ErrorContains(t, svc.Greet("").Err(), "name must not be empty")
+		check.ErrorContains(t, svc.Greet(""), "name must not be empty")
 	})
 }
 
@@ -45,6 +45,6 @@ func TestFakeUsageExample(t *testing.T) {
 	}
 
 	msg, err := fake.Greet("Alice").Unwrap()
-	testutil.NoError(t, err)
+	check.NoError(t, err)
-	testutil.Equal(t, msg, "Hello, Alice!")
+	check.Equal(t, msg, "Hello, Alice!")
 }

pkg/check/check.go

@@ -0,0 +1,93 @@
+// Package check provides lightweight test helpers to reduce boilerplate in
+// table-driven tests.
+//
+// Error-family functions (NoError, Error, ErrorContains) accept either a plain
+// error or a result.Expect[T] value — the package extracts the error from
+// whichever type it receives.
+//
+// Every helper calls t.Helper() so failures are reported at the call site.
+package check
+
+import (
+	"strings"
+	"testing"
+
+	"gitea.djmil.dev/go/template/pkg/result"
+)
+
+// extractErr pulls an error out of v, which must be error or result.Expect[T].
+// Fatally fails the test for any other type.
+func extractErr(t *testing.T, v any) error {
+	t.Helper()
+	if v == nil {
+		return nil
+	}
+	switch x := v.(type) {
+	case error:
+		return x
+	case interface{ Err() error }:
+		return x.Err()
+	default:
+		t.Fatalf("check: unsupported type %T (want error or result.Expect[T])", v)
+		return nil
+	}
+}
+
+// NoError fails the test if v contains a non-nil error.
+func NoError(t *testing.T, v any) {
+	t.Helper()
+	if err := extractErr(t, v); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+// Error fails the test if v contains no error.
+func Error(t *testing.T, v any) {
+	t.Helper()
+	if extractErr(t, v) == nil {
+		t.Fatal("expected error, got nil")
+	}
+}
+
+// ErrorContains fails the test if v contains no error or its message does not
+// contain substr.
+func ErrorContains(t *testing.T, v any, substr string) {
+	t.Helper()
+	err := extractErr(t, v)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+		return
+	}
+	if !strings.Contains(err.Error(), substr) {
+		t.Errorf("error %q does not contain %q", err.Error(), substr)
+	}
+}
+
+// Equal fails the test if got != want.
+func Equal[T comparable](t *testing.T, got, want T) {
+	t.Helper()
+	if got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}
+
+// Ok fails the test if r holds an error, then returns the value.
+func Ok[T any](t *testing.T, r result.Expect[T]) T {
+	t.Helper()
+	if r.Err() != nil {
+		t.Fatalf("unexpected error: %v", r.Err())
+	}
+	return r.Value()
+}
+
+// OkNotNil fails the test if r holds an error or its value is the zero value.
+// T must be a pointer or comparable type where zero means absent.
+func OkNotNil[T comparable](t *testing.T, r result.Expect[T]) T {
+	t.Helper()
+	v := Ok(t, r)
+	var zero T
+	if v == zero {
+		t.Fatal("expected non-nil value, got zero")
+	}
+	return v
+}

pkg/logger/logger_test.go

@@ -3,8 +3,8 @@ package logger_test
 import (
 	"testing"
 
+	"gitea.djmil.dev/go/template/pkg/check"
 	"gitea.djmil.dev/go/template/pkg/logger"
-	"gitea.djmil.dev/go/template/pkg/testutil"
 )
 
 func TestNewCLI(t *testing.T) {
@@ -24,10 +24,10 @@ func TestNewCLI(t *testing.T) {
 			// In tests stderr is not a terminal — NewCLI uses JSON path.
 			r := logger.NewCLI(tc.level, nil)
 			if tc.wantErr {
-				testutil.ResultErr(t, r)
+				check.Error(t, r)
 				return
 			}
-			testutil.ResultOkNotNil(t, r)
+			check.OkNotNil(t, r)
 		})
 	}
 }
@@ -49,10 +49,10 @@ func TestNew(t *testing.T) {
 		t.Run(tc.level, func(t *testing.T) {
 			r := logger.New(tc.level)
 			if tc.wantErr {
-				testutil.ResultErr(t, r)
+				check.Error(t, r)
 				return
 			}
-			testutil.ResultOkNotNil(t, r)
+			check.OkNotNil(t, r)
 		})
 	}
 }

pkg/testutil/testutil.go

@@ -1,75 +0,0 @@
-// Package testutil provides lightweight test helpers to reduce boilerplate in
-// table-driven tests.
-//
-// Every helper calls t.Helper() so failures are reported at the call site, not
-// inside this package.
-package testutil
-
-import (
-	"strings"
-	"testing"
-
-	"gitea.djmil.dev/go/template/pkg/result"
-)
-
-// NoError fails the test immediately if err is not nil.
-func NoError(t *testing.T, err error) {
-	t.Helper()
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-}
-
-// Error fails the test if err is nil.
-func Error(t *testing.T, err error) {
-	t.Helper()
-	if err == nil {
-		t.Fatal("expected error, got nil")
-	}
-}
-
-// ErrorContains fails the test if err is nil or its message does not contain substr.
-func ErrorContains(t *testing.T, err error, substr string) {
-	t.Helper()
-	Error(t, err)
-	if !strings.Contains(err.Error(), substr) {
-		t.Errorf("error %q does not contain %q", err.Error(), substr)
-	}
-}
-
-// Equal fails the test if got != want.
-func Equal[T comparable](t *testing.T, got, want T) {
-	t.Helper()
-	if got != want {
-		t.Errorf("got %v, want %v", got, want)
-	}
-}
-
-// ResultOk fails the test if r holds an error, then returns the value.
-func ResultOk[T any](t *testing.T, r result.Expect[T]) T {
-	t.Helper()
-	if r.Err() != nil {
-		t.Fatalf("unexpected error: %v", r.Err())
-	}
-	return r.Value()
-}
-
-// ResultOkNotNil fails the test if r holds an error or its value is nil.
-// T must be a pointer type.
-func ResultOkNotNil[T comparable](t *testing.T, r result.Expect[T]) T {
-	t.Helper()
-	v := ResultOk(t, r)
-	var zero T
-	if v == zero {
-		t.Fatal("expected non-nil value, got nil")
-	}
-	return v
-}
-
-// ResultErr fails the test if r does not hold an error.
-func ResultErr[T any](t *testing.T, r result.Expect[T]) {
-	t.Helper()
-	if r.Err() == nil {
-		t.Fatal("expected error, got nil")
-	}
-}