1 files changed, 76 insertions, 0 deletions
diff --git a/src/testing/run_example_js.go b/src/testing/run_example_js.go
new file mode 100644
index 0000000..572c6b3
--- /dev/null
+++ b/src/testing/run_example_js.go
@@ -0,0 +1,76 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build js
+
+package testing
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"time"
+)
+
+// TODO(@musiol, @odeke-em): unify this code back into
+// example.go when js/wasm gets an os.Pipe implementation.
+func runExample(eg InternalExample) (ok bool) {
+	if chatty.on {
+		fmt.Printf("%s=== RUN   %s\n", chatty.prefix(), eg.Name)
+	}
+
+	// Capture stdout to temporary file. We're not using
+	// os.Pipe because it is not supported on js/wasm.
+	stdout := os.Stdout
+	f := createTempFile(eg.Name)
+	os.Stdout = f
+	finished := false
+	start := time.Now()
+
+	// Clean up in a deferred call so we can recover if the example panics.
+	defer func() {
+		timeSpent := time.Since(start)
+
+		// Restore stdout, get output and remove temporary file.
+		os.Stdout = stdout
+		var buf strings.Builder
+		_, seekErr := f.Seek(0, io.SeekStart)
+		_, readErr := io.Copy(&buf, f)
+		out := buf.String()
+		f.Close()
+		os.Remove(f.Name())
+		if seekErr != nil {
+			fmt.Fprintf(os.Stderr, "testing: seek temp file: %v\n", seekErr)
+			os.Exit(1)
+		}
+		if readErr != nil {
+			fmt.Fprintf(os.Stderr, "testing: read temp file: %v\n", readErr)
+			os.Exit(1)
+		}
+
+		err := recover()
+		ok = eg.processRunResult(out, timeSpent, finished, err)
+	}()
+
+	// Run example.
+	eg.F()
+	finished = true
+	return
+}
+
+func createTempFile(exampleName string) *os.File {
+	for i := 0; ; i++ {
+		name := fmt.Sprintf("%s/go-example-stdout-%s-%d.txt", os.TempDir(), exampleName, i)
+		f, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
+		if err != nil {
+			if os.IsExist(err) {
+				continue
+			}
+			fmt.Fprintf(os.Stderr, "testing: open temp file: %v\n", err)
+			os.Exit(1)
+		}
+		return f
+	}
+}