DEV 559: Refactor CLI and add customizations (#57)

* move snake API structs into a new client package

* add customizations to snake objects

* refactor and add support for passing snake customizations in games

test/test_utils.go

@@ -0,0 +1,38 @@
+package test
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"io/ioutil"
+	"log"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+var updateFixtures = flag.Bool("update-fixtures", false, "Regenerate fixtures in testdata based on current test output")
+
+// RequireJSONMatchesFixture asserts that the JSON text in actual matches the
+// JSON read from filename, without taking into account whitespace and
+// ordering. Files can be specified relative to the calling test (e.g.
+// testdata/example.json). To regenerate the expected test data automatically
+// after making a code change, pass the `-update-fixtures` flag to `go test`.
+func RequireJSONMatchesFixture(t *testing.T, filename string, actual string) {
+	t.Helper()
+
+	if *updateFixtures {
+		var indented bytes.Buffer
+		err := json.Indent(&indented, []byte(actual), "", "  ")
+		require.NoError(t, err, "Failed to indent JSON")
+		err = ioutil.WriteFile(filename, indented.Bytes(), 0644)
+		require.NoError(t, err, "Failed to update fixture", filename)
+
+		log.Printf("Updating fixture file %#v", filename)
+	}
+
+	expectedData, err := ioutil.ReadFile(filename)
+	require.NoError(t, err, "Failed to read fixture", filename)
+
+	require.JSONEq(t, string(expectedData), actual)
+}