Update zip archive handling to match globs as expected (#244)

* Refactor zip file tests

Signed-off-by: Dan Luhring <dan.luhring@anchore.com>

* Add glob support for leading slashes

Signed-off-by: Dan Luhring <dan.luhring@anchore.com>

* Update zip testing to account for glob matching

Signed-off-by: Dan Luhring <dan.luhring@anchore.com>

* Ignore .DS_STORE

Signed-off-by: Dan Luhring <dan.luhring@anchore.com>

* Improve normalization of zip entry names

Signed-off-by: Dan Luhring <dan.luhring@anchore.com>

* Rename zip test helpers file

Signed-off-by: Dan Luhring <dan.luhring@anchore.com>

internal/file/zip_file_helpers_test.go

@@ -0,0 +1,131 @@
+package file
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"syscall"
+	"testing"
+)
+
+var expectedZipArchiveEntries = []string{
+	"some-dir" + string(os.PathSeparator),
+	filepath.Join("some-dir", "a-file.txt"),
+	"b-file.txt",
+	"nested.zip",
+}
+
+// fatalIfError calls the supplied function. If the function returns a non-nil error, t.Fatal(err) is called.
+func fatalIfError(t *testing.T, fn func() error) {
+	t.Helper()
+
+	if fn == nil {
+		return
+	}
+
+	err := fn()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+// createZipArchive creates a new ZIP archive file at destinationArchivePath based on the directory found at
+// sourceDirPath.
+func createZipArchive(t *testing.T, sourceDirPath, destinationArchivePath string) error {
+	t.Helper()
+
+	cwd, err := os.Getwd()
+	if err != nil {
+		return fmt.Errorf("unable to get cwd: %+v", err)
+	}
+
+	cmd := exec.Command("./generate-zip-fixture.sh", destinationArchivePath, path.Base(sourceDirPath))
+	cmd.Dir = filepath.Join(cwd, "test-fixtures")
+
+	if err := cmd.Start(); err != nil {
+		return fmt.Errorf("unable to start generate zip fixture script: %+v", err)
+	}
+
+	if err := cmd.Wait(); err != nil {
+		if exiterr, ok := err.(*exec.ExitError); ok {
+			// The program has exited with an exit code != 0
+
+			// This works on both Unix and Windows. Although package
+			// syscall is generally platform dependent, WaitStatus is
+			// defined for both Unix and Windows and in both cases has
+			// an ExitStatus() method with the same signature.
+			if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+				if status.ExitStatus() != 0 {
+					return fmt.Errorf("failed to generate fixture: rc=%d", status.ExitStatus())
+				}
+			}
+		} else {
+			return fmt.Errorf("unable to get generate fixture script result: %+v", err)
+		}
+	}
+
+	return nil
+}
+
+// setupZipFileTest encapsulates common test setup work for zip file tests. It returns a cleanup function,
+// which should be called (typically deferred) by the caller, the path of the created zip archive, and an error,
+// which should trigger a fatal test failure in the consuming test. The returned cleanup function will never be nil
+// (even if there's an error), and it should always be called.
+func setupZipFileTest(t *testing.T, sourceDirPath string) (func() error, string, error) {
+	t.Helper()
+
+	// Keep track of any needed cleanup work as we go
+	var cleanupFns []func() error
+	cleanup := func(fns []func() error) func() error {
+		return func() error {
+			for _, fn := range fns {
+				err := fn()
+				if err != nil {
+					return err
+				}
+			}
+
+			return nil
+		}
+	}
+
+	archivePrefix, err := ioutil.TempFile("", "syft-ziputil-archive-TEST-")
+	if err != nil {
+		return cleanup(cleanupFns), "", fmt.Errorf("unable to create tempfile: %+v", err)
+	}
+	cleanupFns = append(cleanupFns, func() error { return os.Remove(archivePrefix.Name()) })
+
+	destinationArchiveFilePath := archivePrefix.Name() + ".zip"
+	t.Logf("archive path: %s", destinationArchiveFilePath)
+	err = createZipArchive(t, sourceDirPath, destinationArchiveFilePath)
+	cleanupFns = append(cleanupFns, func() error { return os.Remove(destinationArchiveFilePath) })
+	if err != nil {
+		return cleanup(cleanupFns), "", err
+	}
+
+	cwd, err := os.Getwd()
+	if err != nil {
+		return cleanup(cleanupFns), "", fmt.Errorf("unable to get cwd: %+v", err)
+	}
+
+	t.Logf("running from: %s", cwd)
+
+	return cleanup(cleanupFns), destinationArchiveFilePath, nil
+}
+
+// TODO: Consider moving any non-git asset generation to a task (e.g. make) that's run ahead of running go tests.
+func ensureNestedZipExists(t *testing.T, sourceDirPath string) error {
+	t.Helper()
+
+	nestedArchiveFilePath := path.Join(sourceDirPath, "nested.zip")
+	err := createZipArchive(t, sourceDirPath, nestedArchiveFilePath)
+
+	if err != nil {
+		return fmt.Errorf("unable to create nested archive for test fixture: %+v", err)
+	}
+
+	return nil
+}