Add common method setOutputWriter

src/testing/benchmark.go

@@ -755,7 +755,7 @@ func (s *benchState) processBench(b *B) {
 					benchFunc: b.benchFunc,
 					benchTime: b.benchTime,
 				}
-				b.o = b.newOutputWriter()
+				b.setOutputWriter()
 				b.run1()
 			}
 			r := b.doBench()
@@ -832,7 +832,7 @@ func (b *B) Run(name string, f func(b *B)) bool {
 		benchTime:  b.benchTime,
 		bstate:     b.bstate,
 	}
-	sub.o = sub.newOutputWriter()
+	sub.setOutputWriter()
 	if partial {
 		// Partial name match, like -bench=X/Y matching BenchmarkX.
 		// Only process sub-benchmarks, if any.
@@ -1009,7 +1009,7 @@ func Benchmark(f func(b *B)) BenchmarkResult {
 		benchFunc: f,
 		benchTime: benchTime,
 	}
-	b.o = b.newOutputWriter()
+	b.setOutputWriter()
 	if b.run1() {
 		b.run()
 	}

src/testing/fuzz.go

@@ -320,7 +320,7 @@ func (f *F) Fuzz(ff any) {
 			t.parent.w = captureOut
 		}
 		t.w = indenter{&t.common}
-		t.o = t.newOutputWriter()
+		t.setOutputWriter()
 		if t.chatty != nil {
 			t.chatty.Updatef(t.name, "=== RUN   %s\n", t.name)
 		}
@@ -530,7 +530,7 @@ func runFuzzTests(deps testDeps, fuzzTests []InternalFuzzTarget, deadline time.T
 					fstate: fstate,
 				}
 				f.w = indenter{&f.common}
-				f.o = f.newOutputWriter()
+				f.setOutputWriter()
 				if f.chatty != nil {
 					f.chatty.Updatef(f.name, "=== RUN   %s\n", f.name)
 				}

src/testing/testing.go

@@ -1046,9 +1046,9 @@ func (c *common) callSite(skip int) string {
 	return fmt.Sprintf("%s:%d: ", file, line)
 }
 
-// newOutputWriter initializes a new outputWriter.
-func (c *common) newOutputWriter() io.Writer {
-	return &outputWriter{c: c}
+// setOutputWriter initializes an outputWriter and sets it as a common field.
+func (c *common) setOutputWriter() {
+	c.o = &outputWriter{c: c}
 }
 
 // outputWriter buffers, formats and writes input.
@@ -1871,7 +1871,7 @@ func (t *T) Run(name string, f func(t *T)) bool {
 		tstate: t.tstate,
 	}
 	t.w = indenter{&t.common}
-	t.o = t.newOutputWriter()
+	t.setOutputWriter()
 
 	if t.chatty != nil {
 		t.chatty.Updatef(t.name, "=== RUN   %s\n", t.name)