chore: modify CLI tests to inject stdout so mutating os.Stdout isn't necessary

Author: stainless-app[bot]

pkg/cmd/cmdutil.go

@@ -193,21 +193,24 @@ func streamToStdout(generateOutput func(w *os.File) error) error {
 	return err
 }
 
-func writeBinaryResponse(response *http.Response, outfile string) (string, error) {
+// writeBinaryResponse writes a binary response to stdout or a file.
+//
+// Takes in a stdout reference so we can test this function without overriding os.Stdout in tests.
+func writeBinaryResponse(response *http.Response, stdout io.Writer, outfile string) (string, error) {
 	defer response.Body.Close()
 	body, err := io.ReadAll(response.Body)
 	if err != nil {
 		return "", err
 	}
 	switch outfile {
 	case "-", "/dev/stdout":
-		_, err := os.Stdout.Write(body)
+		_, err := stdout.Write(body)
 		return "", err
 	case "":
 		// If output file is unspecified, then print to stdout for plain text or
 		// if stdout is not a terminal:
 		if !isTerminal(os.Stdout) || isUTF8TextFile(body) {
-			_, err := os.Stdout.Write(body)
+			_, err := stdout.Write(body)
 			return "", err
 		}
 

pkg/cmd/cmdutil_test.go

@@ -32,7 +32,7 @@ func TestWriteBinaryResponse(t *testing.T) {
 			Body: io.NopCloser(bytes.NewReader(body)),
 		}
 
-		msg, err := writeBinaryResponse(resp, outfile)
+		msg, err := writeBinaryResponse(resp, os.Stdout, outfile)
 
 		require.NoError(t, err)
 		assert.Contains(t, msg, outfile)
@@ -43,24 +43,17 @@ func TestWriteBinaryResponse(t *testing.T) {
 	})
 
 	t.Run("write to stdout", func(t *testing.T) {
-		oldStdout := os.Stdout
-		r, w, _ := os.Pipe()
-		os.Stdout = w
+		t.Parallel()
 
+		var buf bytes.Buffer
 		body := []byte("stdout content")
 		resp := &http.Response{
 			Body: io.NopCloser(bytes.NewReader(body)),
 		}
-		msg, err := writeBinaryResponse(resp, "-")
-
-		w.Close()
-		os.Stdout = oldStdout
+		msg, err := writeBinaryResponse(resp, &buf, "-")
 
 		require.NoError(t, err)
 		assert.Empty(t, msg)
-
-		var buf bytes.Buffer
-		_, _ = buf.ReadFrom(r)
 		assert.Equal(t, body, buf.Bytes())
 	})
 }