net: make use of testing.Errorf instead of testing.Fatalf in non-test function goroutines

See testing.FailNow for further information.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/75900043

src/pkg/net/fd_mutex_test.go

@@ -63,7 +63,8 @@ func TestMutexCloseUnblock(t *testing.T) {
 	for i := 0; i < 4; i++ {
 		go func() {
 			if mu.RWLock(true) {
-				t.Fatal("broken")
+				t.Error("broken")
+				return
 			}
 			c <- true
 		}()
@@ -138,36 +139,44 @@ func TestMutexStress(t *testing.T) {
 				switch r.Intn(3) {
 				case 0:
 					if !mu.Incref() {
-						t.Fatal("broken")
+						t.Error("broken")
+						return
 					}
 					if mu.Decref() {
-						t.Fatal("broken")
+						t.Error("broken")
+						return
 					}
 				case 1:
 					if !mu.RWLock(true) {
-						t.Fatal("broken")
+						t.Error("broken")
+						return
 					}
 					// Ensure that it provides mutual exclusion for readers.
 					if readState[0] != readState[1] {
-						t.Fatal("broken")
+						t.Error("broken")
+						return
 					}
 					readState[0]++
 					readState[1]++
 					if mu.RWUnlock(true) {
-						t.Fatal("broken")
+						t.Error("broken")
+						return
 					}
 				case 2:
 					if !mu.RWLock(false) {
-						t.Fatal("broken")
+						t.Error("broken")
+						return
 					}
 					// Ensure that it provides mutual exclusion for writers.
 					if writeState[0] != writeState[1] {
-						t.Fatal("broken")
+						t.Error("broken")
+						return
 					}
 					writeState[0]++
 					writeState[1]++
 					if mu.RWUnlock(false) {
-						t.Fatal("broken")
+						t.Error("broken")
+						return
 					}
 				}
 			}

src/pkg/net/net_test.go

@@ -28,12 +28,14 @@ func TestShutdown(t *testing.T) {
 		defer ln.Close()
 		c, err := ln.Accept()
 		if err != nil {
-			t.Fatalf("Accept: %v", err)
+			t.Errorf("Accept: %v", err)
+			return
 		}
 		var buf [10]byte
 		n, err := c.Read(buf[:])
 		if n != 0 || err != io.EOF {
-			t.Fatalf("server Read = %d, %v; want 0, io.EOF", n, err)
+			t.Errorf("server Read = %d, %v; want 0, io.EOF", n, err)
+			return
 		}
 		c.Write([]byte("response"))
 		c.Close()
@@ -84,12 +86,14 @@ func TestShutdownUnix(t *testing.T) {
 	go func() {
 		c, err := ln.Accept()
 		if err != nil {
-			t.Fatalf("Accept: %v", err)
+			t.Errorf("Accept: %v", err)
+			return
 		}
 		var buf [10]byte
 		n, err := c.Read(buf[:])
 		if n != 0 || err != io.EOF {
-			t.Fatalf("server Read = %d, %v; want 0, io.EOF", n, err)
+			t.Errorf("server Read = %d, %v; want 0, io.EOF", n, err)
+			return
 		}
 		c.Write([]byte("response"))
 		c.Close()
@@ -196,7 +200,8 @@ func TestTCPClose(t *testing.T) {
 	go func() {
 		c, err := Dial("tcp", l.Addr().String())
 		if err != nil {
-			t.Fatal(err)
+			t.Errorf("Dial: %v", err)
+			return
 		}
 
 		go read(c)

src/pkg/net/tcp_test.go

@@ -185,7 +185,8 @@ func benchmarkTCPConcurrentReadWrite(b *testing.B, laddr string) {
 		for p := 0; p < P; p++ {
 			s, err := ln.Accept()
 			if err != nil {
-				b.Fatalf("Accept failed: %v", err)
+				b.Errorf("Accept failed: %v", err)
+				return
 			}
 			servers[p] = s
 		}
@@ -217,7 +218,8 @@ func benchmarkTCPConcurrentReadWrite(b *testing.B, laddr string) {
 				buf[0] = v
 				_, err := c.Write(buf[:])
 				if err != nil {
-					b.Fatalf("Write failed: %v", err)
+					b.Errorf("Write failed: %v", err)
+					return
 				}
 			}
 		}(clients[p])
@@ -232,7 +234,8 @@ func benchmarkTCPConcurrentReadWrite(b *testing.B, laddr string) {
 			for i := 0; i < N; i++ {
 				_, err := s.Read(buf[:])
 				if err != nil {
-					b.Fatalf("Read failed: %v", err)
+					b.Errorf("Read failed: %v", err)
+					return
 				}
 				pipe <- buf[0]
 			}
@@ -250,7 +253,8 @@ func benchmarkTCPConcurrentReadWrite(b *testing.B, laddr string) {
 				buf[0] = v
 				_, err := s.Write(buf[:])
 				if err != nil {
-					b.Fatalf("Write failed: %v", err)
+					b.Errorf("Write failed: %v", err)
+					return
 				}
 			}
 			s.Close()
@@ -263,7 +267,8 @@ func benchmarkTCPConcurrentReadWrite(b *testing.B, laddr string) {
 			for i := 0; i < N; i++ {
 				_, err := c.Read(buf[:])
 				if err != nil {
-					b.Fatalf("Read failed: %v", err)
+					b.Errorf("Read failed: %v", err)
+					return
 				}
 			}
 			c.Close()

src/pkg/net/timeout_test.go

@@ -348,7 +348,8 @@ func TestReadWriteDeadline(t *testing.T) {
 	go func() {
 		c, err := ln.Accept()
 		if err != nil {
-			t.Fatalf("Accept: %v", err)
+			t.Errorf("Accept: %v", err)
+			return
 		}
 		defer c.Close()
 		lnquit <- true
@@ -536,7 +537,8 @@ func TestReadDeadlineDataAvailable(t *testing.T) {
 	go func() {
 		c, err := ln.Accept()
 		if err != nil {
-			t.Fatalf("Accept: %v", err)
+			t.Errorf("Accept: %v", err)
+			return
 		}
 		defer c.Close()
 		n, err := c.Write([]byte(msg))
@@ -574,7 +576,8 @@ func TestWriteDeadlineBufferAvailable(t *testing.T) {
 	go func() {
 		c, err := ln.Accept()
 		if err != nil {
-			t.Fatalf("Accept: %v", err)
+			t.Errorf("Accept: %v", err)
+			return
 		}
 		defer c.Close()
 		c.SetWriteDeadline(time.Now().Add(-5 * time.Second)) // in the past
@@ -610,7 +613,8 @@ func TestAcceptDeadlineConnectionAvailable(t *testing.T) {
 	go func() {
 		c, err := Dial("tcp", ln.Addr().String())
 		if err != nil {
-			t.Fatalf("Dial: %v", err)
+			t.Errorf("Dial: %v", err)
+			return
 		}
 		defer c.Close()
 		var buf [1]byte
@@ -669,7 +673,8 @@ func TestProlongTimeout(t *testing.T) {
 		s, err := ln.Accept()
 		connected <- true
 		if err != nil {
-			t.Fatalf("ln.Accept: %v", err)
+			t.Errorf("ln.Accept: %v", err)
+			return
 		}
 		defer s.Close()
 		s.SetDeadline(time.Now().Add(time.Hour))