.

go/internal/xtracing/tracetest/example_test.go

@@ -156,6 +156,22 @@ func TestDeadlock(t *testing.T) {
 	}, "-tracetest.deadtime=0.5s")
 }
 
+// TestExpectType demonstrates Expect asserting with "unexpected event type".
+func TestExpectType(t *testing.T) {
+	verify(t, func(t *tracetest.T) {
+		var wg sync.WaitGroup
+		defer wg.Wait()
+		wg.Add(1)
+
+		go func() { // thread 1
+			defer wg.Done()
+			hi("T1·A")
+		}()
+
+		t.Expect("t1", eventHello("T1·A"))
+	})
+}
+
 // XXX race bug with sleep caught only by delay injection
 
 
@@ -231,6 +247,7 @@ type testExpect struct {
 // testExpectMap maps <test name> -> testExpect.
 var testExpectMap = map[string]testExpect{
 	"Test2ThreadsOK": {0, ""},
+
 	"TestDeadlock":   {1,
 `--- FAIL: TestDeadlock (<TIME>)
     example_test.go:155: t2: recv: deadlock waiting for *tracetest_test.eventHi
@@ -240,4 +257,13 @@ var testExpectMap = map[string]testExpect{
 
     tracetest.go:<LINE>: t1: send: canceled (test failed)
 `},
+
+	"TestExpectType": {1,
+`--- FAIL: TestExpectType (<TIME>)
+    example_test.go:171: t1: expect: tracetest_test.eventHello:  got tracetest_test.eventHi T1·A
+    example_test.go:171: test shutdown: #streams: 1,  #(pending events): 0
+        # t1
+
+    tracetest.go:<LINE>: t1: send: unexpected event type
+`},
 }