cmd/otk-resolve-containers: add raw JSON test

Add an extra test that generates a raw json string as input and checks
the raw json string from the output.  This test resolves only one
container to make the construction of the output less tedious and avoid
the need to predict and verify the order of the results.

cmd/otk-resolve-containers/main_test.go

@@ -185,3 +185,67 @@ func TestResolverUnhappy(t *testing.T) {
 		})
 	}
 }
+
+func TestResolverRawJSON(t *testing.T) {
+	require := require.New(t)
+
+	registry, refs := createTestRegistry()
+	defer registry.Close()
+
+	inpContainers := make([]blueprint.Container, len(refs))
+	for idx, ref := range refs {
+		inpContainers[idx] = blueprint.Container{
+			Source:       ref,
+			Name:         fmt.Sprintf("test/localhost/%s", ref), // add a prefix for the local name to override the source
+			TLSVerify:    common.ToPtr(false),
+			LocalStorage: false,
+		}
+	}
+
+	for _, containerArch := range []string{"amd64", "ppc64le"} {
+		t.Run(containerArch, func(t *testing.T) {
+			cntName := fmt.Sprintf("test/localhost/%s", refs[0])
+			inpBuf := bytes.NewBufferString(fmt.Sprintf(`{
+"tree":{
+  "arch":"%s",
+  "containers":[
+    {
+      "source":"%s",
+      "name":"%s",
+      "tls-verify":false
+    }
+  ]
+ }
+}`, containerArch, refs[0], cntName))
+			outBuf := &bytes.Buffer{}
+
+			err := resolver.Run(inpBuf, outBuf)
+			require.NoError(err)
+
+			// resolve directly with the registry and convert to a raw JSON
+			// string to compare with output
+			spec, err := registry.Resolve(refs[0], arch.FromString(containerArch))
+			require.NoError(err)
+
+			expected := fmt.Sprintf(`{
+  "tree": {
+    "const": {
+      "containers": [
+        {
+          "source": "%s",
+          "digest": "%s",
+          "imageid": "%s",
+          "local-name": "%s",
+          "list-digest": "%s",
+          "arch": "%s",
+          "tls-verify": %v
+        }
+      ]
+    }
+  }
+}
+`, spec.Source, spec.Digest, spec.ImageID, fmt.Sprintf("test/localhost/%s", refs[0]), spec.ListDigest, spec.Arch, *spec.TLSVerify)
+			require.Equal(expected, outBuf.String())
+		})
+	}
+}