Add fakes library: recursive JSON template engine, i18n locales, Docker workflow

fakes_test.go

@@ -0,0 +1,60 @@
+package fakes
+
+import (
+	"strings"
+	"testing"
+)
+
+// newFakes creates a faker for a locale directory, failing the test on error.
+func newFakes(t *testing.T, dir string, opts ...Option) *Fakes {
+	t.Helper()
+	f, err := New(dir, opts...)
+	if err != nil {
+		t.Fatalf("New(%q): %v", dir, err)
+	}
+	return f
+}
+
+// fake generates a value, failing the test on error.
+func fake(t *testing.T, f *Fakes, path string) string {
+	t.Helper()
+	s, err := f.Fake(path)
+	if err != nil {
+		t.Fatalf("Fake(%q): %v", path, err)
+	}
+	return s
+}
+
+func TestNewRejectsNonFullLocale(t *testing.T) {
+	for _, bad := range []string{"locales/sv", "locales/se", "locales/swedish", "locales/sv_S"} {
+		if _, err := New(bad); err == nil {
+			t.Errorf("New(%q) = nil error, want full-locale error", bad)
+		}
+	}
+}
+
+func TestNewMissingDirectory(t *testing.T) {
+	_, err := New("locales/de_DE")
+	if err == nil || !strings.Contains(err.Error(), "de_DE") {
+		t.Fatalf("New(missing) error = %v, want it to name the locale", err)
+	}
+}
+
+func TestWithSeedIsDeterministic(t *testing.T) {
+	a, b := newFakes(t, "locales/sv_SE", WithSeed(42)), newFakes(t, "locales/sv_SE", WithSeed(42))
+	for i := 0; i < 50; i++ {
+		if x, y := fake(t, a, "person"), fake(t, b, "person"); x != y {
+			t.Fatalf("same seed diverged at %d: %q != %q", i, x, y)
+		}
+	}
+}
+
+func TestDifferentSeedsDiffer(t *testing.T) {
+	a, b := newFakes(t, "locales/en_US", WithSeed(1)), newFakes(t, "locales/en_US", WithSeed(2))
+	for i := 0; i < 50; i++ {
+		if fake(t, a, "person") != fake(t, b, "person") {
+			return
+		}
+	}
+	t.Fatal("seeds 1 and 2 produced identical sequences")
+}