Add notes to relevant tests.

These were out-of-band notes that can help provide additional context
and simplify automated imports.

PiperOrigin-RevId: 293525915

1 files changed, 75 insertions, 0 deletions

diff --git a/runsc/testutil/testutil_runfiles.go b/runsc/testutil/testutil_runfiles.go
new file mode 100644
index 000000000..ece9ea9a1
--- /dev/null
+++ b/runsc/testutil/testutil_runfiles.go
@@ -0,0 +1,75 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package testutil
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// FindFile searchs for a file inside the test run environment. It returns the
+// full path to the file. It fails if none or more than one file is found.
+func FindFile(path string) (string, error) {
+	wd, err := os.Getwd()
+	if err != nil {
+		return "", err
+	}
+
+	// The test root is demarcated by a path element called "__main__". Search for
+	// it backwards from the working directory.
+	root := wd
+	for {
+		dir, name := filepath.Split(root)
+		if name == "__main__" {
+			break
+		}
+		if len(dir) == 0 {
+			return "", fmt.Errorf("directory __main__ not found in %q", wd)
+		}
+		// Remove ending slash to loop around.
+		root = dir[:len(dir)-1]
+	}
+
+	// Annoyingly, bazel adds the build type to the directory path for go
+	// binaries, but not for c++ binaries. We use two different patterns to
+	// to find our file.
+	patterns := []string{
+		// Try the obvious path first.
+		filepath.Join(root, path),
+		// If it was a go binary, use a wildcard to match the build
+		// type. The pattern is: /test-path/__main__/directories/*/file.
+		filepath.Join(root, filepath.Dir(path), "*", filepath.Base(path)),
+	}
+
+	for _, p := range patterns {
+		matches, err := filepath.Glob(p)
+		if err != nil {
+			// "The only possible returned error is ErrBadPattern,
+			// when pattern is malformed." -godoc
+			return "", fmt.Errorf("error globbing %q: %v", p, err)
+		}
+		switch len(matches) {
+		case 0:
+			// Try the next pattern.
+		case 1:
+			// We found it.
+			return matches[0], nil
+		default:
+			return "", fmt.Errorf("more than one match found for %q: %s", path, matches)
+		}
+	}
+	return "", fmt.Errorf("file %q not found", path)
+}