more explicit workdir check for builder, closes #139

builder.go

@@ -85,30 +85,42 @@ func Build(bin string) error {
 			return fmt.Errorf("failed to compile package: %s, reason: %v, output: %s", pkg.Name, err, string(out))
 		}
 
-		// let go do the dirty work and compile test
-		// package with it's dependencies. Older go
-		// versions does not accept existing file output
-		// so we create a temporary executable which will
-		// removed.
-		temp := fmt.Sprintf(filepath.Join("%s", "temp-%d.test"), os.TempDir(), time.Now().UnixNano())
-
-		// builds and compile the tested package.
+		// build and compile the tested package.
 		// generated test executable will be removed
 		// since we do not need it for godog suite.
 		// we also print back the temp WORK directory
 		// go has built. We will reuse it for our suite workdir.
-		out, err = exec.Command("go", "test", "-c", "-work", "-o", temp).CombinedOutput()
+		out, err = exec.Command("go", "test", "-c", "-work", "-o", os.DevNull).CombinedOutput()
 		if err != nil {
 			return fmt.Errorf("failed to compile tested package: %s, reason: %v, output: %s", pkg.Name, err, string(out))
 		}
-		defer os.Remove(temp)
 
 		// extract go-build temporary directory as our workdir
-		workdir = strings.TrimSpace(string(out))
-		if !strings.HasPrefix(workdir, "WORK=") {
-			return fmt.Errorf("expected WORK dir path, but got: %s", workdir)
+		lines := strings.Split(strings.TrimSpace(string(out)), "\n")
+		// it may have some compilation warnings, in the output, but these are not
+		// considered to be errors, since command exit status is 0
+		for _, ln := range lines {
+			if !strings.HasPrefix(ln, "WORK=") {
+				continue
+			}
+			workdir = strings.Replace(ln, "WORK=", "", 1)
+			break
+		}
+
+		// may not locate it in output
+		if workdir == testdir {
+			return fmt.Errorf("expected WORK dir path to be present in output: %s", string(out))
+		}
+
+		// check whether workdir exists
+		stats, err := os.Stat(workdir)
+		if os.IsNotExist(err) {
+			return fmt.Errorf("expected WORK dir: %s to be available", workdir)
+		}
+
+		if !stats.IsDir() {
+			return fmt.Errorf("expected WORK dir: %s to be directory", workdir)
 		}
-		workdir = strings.Replace(workdir, "WORK=", "", 1)
 		testdir = filepath.Join(workdir, pkg.ImportPath, "_test")
 	} else {
 		// still need to create temporary workdir

builder_go110.go

@@ -87,7 +87,7 @@ func Build(bin string) error {
 			return fmt.Errorf("failed to compile package: %s, reason: %v, output: %s", pkg.Name, err, string(out))
 		}
 
-		// builds and compile the tested package.
+		// build and compile the tested package.
 		// generated test executable will be removed
 		// since we do not need it for godog suite.
 		// we also print back the temp WORK directory
@@ -98,11 +98,31 @@ func Build(bin string) error {
 		}
 
 		// extract go-build temporary directory as our workdir
-		workdir = strings.TrimSpace(string(out))
-		if !strings.HasPrefix(workdir, "WORK=") {
-			return fmt.Errorf("expected WORK dir path, but got: %s", workdir)
+		lines := strings.Split(strings.TrimSpace(string(out)), "\n")
+		// it may have some compilation warnings, in the output, but these are not
+		// considered to be errors, since command exit status is 0
+		for _, ln := range lines {
+			if !strings.HasPrefix(ln, "WORK=") {
+				continue
+			}
+			workdir = strings.Replace(ln, "WORK=", "", 1)
+			break
+		}
+
+		// may not locate it in output
+		if workdir == testdir {
+			return fmt.Errorf("expected WORK dir path to be present in output: %s", string(out))
+		}
+
+		// check whether workdir exists
+		stats, err := os.Stat(workdir)
+		if os.IsNotExist(err) {
+			return fmt.Errorf("expected WORK dir: %s to be available", workdir)
+		}
+
+		if !stats.IsDir() {
+			return fmt.Errorf("expected WORK dir: %s to be directory", workdir)
 		}
-		workdir = strings.Replace(workdir, "WORK=", "", 1)
 		testdir = filepath.Join(workdir, "b001")
 	} else {
 		// still need to create temporary workdir