1 files changed, 46 insertions, 0 deletions
diff --git a/internal/testutil/exec.go b/internal/testutil/exec.go
new file mode 100644
index 00000000..eee1677b
--- /dev/null
+++ b/internal/testutil/exec.go
@@ -0,0 +1,46 @@
+// Copyright 2020 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package testutil
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+// Exec executes "go test" on given helper with supplied environment variables.
+// It is useful to mock "os/exec" functions in tests. When succeeded, it returns
+// the result produced by the test helper.
+// The test helper should:
+//     1. Use WantHelperProcess function to determine if it is being called in helper mode.
+//     2. Call fmt.Fprintln(os.Stdout, ...) to print results for the main test to collect.
+func Exec(helper string, envs ...string) (string, error) {
+	cmd := exec.Command(os.Args[0], "-test.run="+helper, "--")
+	cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
+	cmd.Env = append(cmd.Env, envs...)
+	out, err := cmd.CombinedOutput()
+	str := string(out)
+	if err != nil {
+		return "", fmt.Errorf("%v - %s", err, str)
+	}
+
+	if strings.Contains(str, "no tests to run") {
+		return "", errors.New("no tests to run")
+	} else if !strings.Contains(str, "PASS") {
+		return "", errors.New(str)
+	}
+
+	// Collect helper result
+	result := str[:strings.Index(str, "PASS")]
+	result = strings.TrimSpace(result)
+	return result, nil
+}
+
+// WantHelperProcess returns true if current process is in helper mode.
+func WantHelperProcess() bool {
+	return os.Getenv("GO_WANT_HELPER_PROCESS") == "1"
+}