io: add test for Pipe constructor allocations

Updates golang#67633 Change-Id: If3da9317ba36cb8a7868db94b45c402e1793e018 Reviewed-on: https://go-review.googlesource.com/c/go/+/588219 Auto-Submit: Cuong Manh Le <[email protected]> Auto-Submit: Ian Lance Taylor <[email protected]> Reviewed-by: Mateusz Poliwczak <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]> LUCI-TryBot-Result: Go LUCI <[email protected]> Reviewed-by: Than McIntosh <[email protected]>
yesudeep · Jul 7, 2024 · b43d6c5 · b43d6c5
1 parent d0146bd
commit b43d6c5
Showing 1 changed file with 18 additions and 0 deletions.
diff --git a/src/io/pipe_test.go b/src/io/pipe_test.go
@@ -421,3 +421,21 @@ func sortBytesInGroups(b []byte, n int) []byte {
 	slices.SortFunc(groups, bytes.Compare)
 	return bytes.Join(groups, nil)
 }
+
+var (
+	rSink *PipeReader
+	wSink *PipeWriter
+)
+
+func TestPipeAllocations(t *testing.T) {
+	numAllocs := testing.AllocsPerRun(10, func() {
+		rSink, wSink = Pipe()
+	})
+
+	// go.dev/cl/473535 claimed Pipe() should only do 2 allocations,
+	// plus the 2 escaping to heap for simulating real world usages.
+	expectedAllocs := 4
+	if int(numAllocs) > expectedAllocs {
+		t.Fatalf("too many allocations for io.Pipe() call: %f", numAllocs)
+	}
+}