func skipIfGccgo(t *testing.T, msg string) {
	if runtime.Compiler == "gccgo" {
		t.Skipf("skipping test not supported on gccgo: %s", msg)
	}
}

// testgo sets up for a test that runs testgo.
func testgo(t *testing.T) *testgoData {
	t.Helper()
	testenv.MustHaveGoBuild(t)
	testenv.SkipIfShortAndSlow(t)

	return &testgoData{t: t}
}

// must gives a fatal error if err is not nil.

		os.Exit(2)
	}
	if *testlog != "" {
		// Note: Not using toOutputDir.
		// This file is for use by cmd/go, not users.
		var f *os.File
		var err error
		if m.numRun == 1 {
			f, err = os.Create(*testlog)
		} else {
			f, err = os.OpenFile(*testlog, os.O_WRONLY, 0)
			if err == nil {
				f.Seek(0, io.SeekEnd)
			}
		}

				case '?':
					test |= TEST_VERIFY;
					test &= ~(TEST_AND|TEST_OR);
					state.verify = state.passed;
					continue;
				case '&':
					test |= TEST_VERIFY|TEST_AND;
					test &= ~TEST_OR;
					continue;
				case '|':
					test |= TEST_VERIFY|TEST_OR;
					test &= ~TEST_AND;
					continue;
				case ';':
					test |= TEST_OR;
					test &= ~TEST_AND;
					continue;

				case '{':

	testlog, err := os.ReadFile(a.Objdir + "testlog.txt")
	if err != nil || !bytes.HasPrefix(testlog, testlogMagic) || testlog[len(testlog)-1] != '\n' {
		if cache.DebugTest {
			if err != nil {
				fmt.Fprintf(os.Stderr, "testcache: %s: reading testlog: %v\n", a.Package.ImportPath, err)
			} else {
				fmt.Fprintf(os.Stderr, "testcache: %s: reading testlog: malformed\n", a.Package.ImportPath)
			}

	u1 := new(URL)
	err = json.Unmarshal(js, u1)
	if err != nil {
		t.Fatal(err)
	}
	if u1.String() != u.String() {
		t.Errorf("json decoded to: %s\nwant: %s\n", u1, u)
	}
}

func TestGob(t *testing.T) {
	u, err := Parse("https://www.google.com/x?y=z")
	if err != nil {
		t.Fatal(err)
	}
	var w bytes.Buffer
	err = gob.NewEncoder(&w).Encode(u)
	if err != nil {
		t.Fatal(err)
	}

		if f := Copysign(vfcopysignSC[i], -1); !alike(copysignSC[i], f) {
			t.Errorf("Copysign(%g, -1) = %g, want %g", vfcopysignSC[i], f, copysignSC[i])
		}
	}
}

func TestCos(t *testing.T) {
	for i := 0; i < len(vf); i++ {
		if f := Cos(vf[i]); !veryclose(cos[i], f) {
			t.Errorf("Cos(%g) = %g, want %g", vf[i], f, cos[i])
		}
	}
	for i := 0; i < len(vfcosSC); i++ {