all: fix some vet-caught formatting errors, mostly but not only in tests

Could go in 1.5, although not critical.
See also #12107

Change-Id: I7f1608b58581d21df4db58f0db654fef79e33a90
Reviewed-on: https://go-review.googlesource.com/13481Reviewed-by: Dave Cheney <dave@cheney.net>

src/cmd/internal/rsc.io/arm/armasm/ext_test.go

@@ -178,7 +178,7 @@ func testExtDis(
 	t.Logf("%d test cases, %d expected mismatches, %d failures; %.0f cases/second", totalTests, totalSkips, totalErrors, float64(totalTests)/time.Since(start).Seconds())
 
 	if err := <-errc; err != nil {
-		t.Fatal("external disassembler: %v", err)
+		t.Fatalf("external disassembler: %v", err)
 	}
 
 }

src/cmd/internal/rsc.io/x86/x86asm/ext_test.go

@@ -177,7 +177,7 @@ func testExtDis(
 	t.Logf("%d test cases, %d expected mismatches, %d failures; %.0f cases/second", totalTests, totalSkips, totalErrors, float64(totalTests)/time.Since(start).Seconds())
 
 	if err := <-errc; err != nil {
-		t.Fatal("external disassembler: %v", err)
+		t.Fatalf("external disassembler: %v", err)
 	}
 
 }

src/crypto/ecdsa/ecdsa_test.go

@@ -91,11 +91,11 @@ func testNonceSafety(t *testing.T, c elliptic.Curve, tag string) {
 
 	if s0.Cmp(s1) == 0 {
 		// This should never happen.
-		t.Errorf("%s: the signatures on two different messages were the same")
+		t.Errorf("%s: the signatures on two different messages were the same", tag)
 	}
 
 	if r0.Cmp(r1) == 0 {
-		t.Errorf("%s: the nonce used for two diferent messages was the same")
+		t.Errorf("%s: the nonce used for two diferent messages was the same", tag)
 	}
 }
 
@@ -126,11 +126,11 @@ func testINDCCA(t *testing.T, c elliptic.Curve, tag string) {
 	}
 
 	if s0.Cmp(s1) == 0 {
-		t.Errorf("%s: two signatures of the same message produced the same result")
+		t.Errorf("%s: two signatures of the same message produced the same result", tag)
 	}
 
 	if r0.Cmp(r1) == 0 {
-		t.Errorf("%s: two signatures of the same message produced the same nonce")
+		t.Errorf("%s: two signatures of the same message produced the same nonce", tag)
 	}
 }
 

src/crypto/rsa/pkcs1v15_test.go

@@ -160,7 +160,7 @@ func TestEncryptPKCS1v15DecrypterSessionKey(t *testing.T) {
 		}
 
 		if test.out != "FAIL" && !bytes.Equal(plaintext, []byte(test.out)) {
-			t.Errorf("#%d: incorrect plaintext: got %x, want %x", plaintext, test.out)
+			t.Errorf("#%d: incorrect plaintext: got %x, want %x", i, plaintext, test.out)
 		}
 	}
 }

src/crypto/tls/handshake_server_test.go

@@ -84,7 +84,7 @@ func testClientHelloFailure(t *testing.T, serverConfig *Config, m handshakeMessa
 	s.Close()
 	if len(expectedSubStr) == 0 {
 		if err != nil && err != io.EOF {
-			t.Errorf("Got error: %s; expected to succeed", err, expectedSubStr)
+			t.Errorf("Got error: %s; expected to succeed", err)
 		}
 	} else if err == nil || !strings.Contains(err.Error(), expectedSubStr) {
 		t.Errorf("Got error: %s; expected to match substring '%s'", err, expectedSubStr)

src/encoding/gob/codec_test.go

@@ -1488,7 +1488,7 @@ func TestErrorInvalidTypeId(t *testing.T) {
 		var foo struct{}
 		err := d.Decode(&foo)
 		if err != errBadType {
-			t.Fatal("decode: expected %s, got %s", errBadType, err)
+			t.Fatalf("decode: expected %s, got %s", errBadType, err)
 		}
 	}
 }

src/internal/trace/parser_test.go

@@ -24,7 +24,7 @@ func TestCorruptedInputs(t *testing.T) {
 	for _, data := range tests {
 		events, err := Parse(strings.NewReader(data))
 		if err == nil || events != nil {
-			t.Fatalf("no error on input: %q\n", t)
+			t.Fatalf("no error on input: %q\n", data)
 		}
 	}
 }

src/net/http/transport_test.go

@@ -2645,7 +2645,7 @@ func TestTransportFlushesBodyChunks(t *testing.T) {
 		req.Header.Set("User-Agent", "x") // known value for test
 		res, err := tr.RoundTrip(req)
 		if err != nil {
-			t.Error("RoundTrip: %v", err)
+			t.Errorf("RoundTrip: %v", err)
 			close(resc)
 			return
 		}

src/path/filepath/path_test.go

@@ -402,18 +402,18 @@ func mark(path string, info os.FileInfo, err error, errors *[]error, clear bool)
 func chtmpdir(t *testing.T) (restore func()) {
 	oldwd, err := os.Getwd()
 	if err != nil {
-		t.Fatal("chtmpdir: %v", err)
+		t.Fatalf("chtmpdir: %v", err)
 	}
 	d, err := ioutil.TempDir("", "test")
 	if err != nil {
-		t.Fatal("chtmpdir: %v", err)
+		t.Fatalf("chtmpdir: %v", err)
 	}
 	if err := os.Chdir(d); err != nil {
-		t.Fatal("chtmpdir: %v", err)
+		t.Fatalf("chtmpdir: %v", err)
 	}
 	return func() {
 		if err := os.Chdir(oldwd); err != nil {
-			t.Fatal("chtmpdir: %v", err)
+			t.Fatalf("chtmpdir: %v", err)
 		}
 		os.RemoveAll(d)
 	}