v0.3.1 minor refactor, tests changed to standard library

testhelpers_test.go

@@ -0,0 +1,85 @@
+package auth
+
+import (
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"testing"
+
+	"golang.org/x/crypto/argon2"
+)
+
+// Assertion helpers. Failures are fatal: most tests below are sequential
+// protocol exchanges where continuing past a failure only produces noise.
+
+func noErr(t *testing.T, err error, ctx string) {
+	t.Helper()
+	if err != nil {
+		t.Fatalf("%s: unexpected error: %v", ctx, err)
+	}
+}
+
+func hasErr(t *testing.T, err error, ctx string) {
+	t.Helper()
+	if err == nil {
+		t.Fatalf("%s: expected error, got nil", ctx)
+	}
+}
+
+func errIs(t *testing.T, err, target error, ctx string) {
+	t.Helper()
+	if !errors.Is(err, target) {
+		t.Fatalf("%s: got %v, want %v", ctx, err, target)
+	}
+}
+
+func eq[T comparable](t *testing.T, got, want T, ctx string) {
+	t.Helper()
+	if got != want {
+		t.Fatalf("%s: got %v, want %v", ctx, got, want)
+	}
+}
+
+func eqBytes(t *testing.T, got, want []byte, ctx string) {
+	t.Helper()
+	if !bytes.Equal(got, want) {
+		t.Fatalf("%s: got %x, want %x", ctx, got, want)
+	}
+}
+
+func isTrue(t *testing.T, v bool, ctx string) {
+	t.Helper()
+	if !v {
+		t.Fatalf("%s: got false, want true", ctx)
+	}
+}
+
+// Test KDF cost. Parameter handling is verified independently of parameter
+// magnitude, so every test that does not measure defaults uses these.
+const (
+	testArgonTime    = 1
+	testArgonMemory  = 8 * 1024
+	testArgonThreads = 1
+)
+
+var cheapArgon = []Option{
+	WithTime(testArgonTime),
+	WithMemory(testArgonMemory),
+	WithThreads(testArgonThreads),
+}
+
+// rawB64 encodes n zero bytes in the PHC alphabet.
+func rawB64(n int) string {
+	return base64.RawStdEncoding.EncodeToString(make([]byte, n))
+}
+
+// phcFor builds a PHC record with an arbitrary salt and digest length, which
+// HashPassword cannot produce.
+func phcFor(password string, salt []byte, keyLen uint32) string {
+	digest := argon2.IDKey([]byte(password), salt, testArgonTime, testArgonMemory, testArgonThreads, keyLen)
+	return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
+		argon2.Version, testArgonMemory, testArgonTime, testArgonThreads,
+		base64.RawStdEncoding.EncodeToString(salt),
+		base64.RawStdEncoding.EncodeToString(digest))
+}