Add skopeo registry mirror integration tests

- Update toml to latest release
- Update containers/image
- Add integration tests
- Add hidden `--registry-conf` flag used by the integration tests

Signed-off-by: Sascha Grunert <sgrunert@suse.com>

integration/copy_test.go

@@ -662,3 +662,37 @@ func verifyManifestMIMEType(c *check.C, dir string, expectedMIMEType string) {
 	mimeType := manifest.GuessMIMEType(manifestBlob)
 	c.Assert(mimeType, check.Equals, expectedMIMEType)
 }
+
+const regConfFixture = "./fixtures/registries.conf"
+
+func (s *SkopeoSuite) TestSuccessCopySrcWithMirror(c *check.C) {
+	dir, err := ioutil.TempDir("", "copy-mirror")
+	c.Assert(err, check.IsNil)
+
+	assertSkopeoSucceeds(c, "", "--registries-conf="+regConfFixture, "copy",
+		"docker://mirror.invalid/busybox", "dir:"+dir)
+}
+
+func (s *SkopeoSuite) TestFailureCopySrcWithMirrorsUnavailable(c *check.C) {
+	dir, err := ioutil.TempDir("", "copy-mirror")
+	c.Assert(err, check.IsNil)
+
+	assertSkopeoFails(c, ".*no such host.*", "--registries-conf="+regConfFixture, "copy",
+		"docker://invalid.invalid/busybox", "dir:"+dir)
+}
+
+func (s *SkopeoSuite) TestSuccessCopySrcWithMirrorAndPrefix(c *check.C) {
+	dir, err := ioutil.TempDir("", "copy-mirror")
+	c.Assert(err, check.IsNil)
+
+	assertSkopeoSucceeds(c, "", "--registries-conf="+regConfFixture, "copy",
+		"docker://gcr.invalid/foo/bar/busybox", "dir:"+dir)
+}
+
+func (s *SkopeoSuite) TestFailureCopySrcWithMirrorAndPrefixUnavailable(c *check.C) {
+	dir, err := ioutil.TempDir("", "copy-mirror")
+	c.Assert(err, check.IsNil)
+
+	assertSkopeoFails(c, ".*no such host.*", "--registries-conf="+regConfFixture, "copy",
+		"docker://gcr.invalid/wrong/prefix/busybox", "dir:"+dir)
+}

integration/fixtures/registries.conf

@@ -0,0 +1,28 @@
+[[registry]]
+location = "mirror.invalid"
+mirror = [
+    { location = "mirror-0.invalid" },
+    { location = "mirror-1.invalid" },
+    { location = "gcr.io/google-containers" },
+]
+
+# This entry is currently unused and exists only to ensure
+# that the mirror.invalid/busybox is not rewritten twice.
+[[registry]]
+location = "gcr.io"
+prefix = "gcr.io/google-containers"
+
+[[registry]]
+location = "invalid.invalid"
+mirror = [
+    { location = "invalid-mirror-0.invalid" },
+    { location = "invalid-mirror-1.invalid" },
+]
+
+[[registry]]
+location = "gcr.invalid"
+prefix = "gcr.invalid/foo/bar"
+mirror = [
+    { location = "wrong-mirror-0.invalid" },
+    { location = "gcr.io/google-containers" },
+]