Tests for the shipped data layer, New options and concurrent Fake

shipped_data_test.go

@@ -0,0 +1,114 @@
+package fejkdata
+
+import (
+	"reflect"
+	"slices"
+	"strings"
+	"sync"
+	"testing"
+	"testing/fstest"
+)
+
+func TestNewDefaultsToShippedData(t *testing.T) {
+	f, err := New(WithSeed(1))
+	if err != nil {
+		t.Fatalf("New() = %v", err)
+	}
+	paths := f.List()
+	for _, p := range []string{"sv_SE.person", "en_US.address", "misc.uuid"} {
+		if !slices.Contains(paths, p) {
+			t.Errorf("List() omits shipped %q", p)
+		}
+	}
+	if got := fake(t, f, "sv_SE.person"); got == "" {
+		t.Error("sv_SE.person rendered empty")
+	}
+}
+
+func TestWithDataPathLayersOverShipped(t *testing.T) {
+	dir := writeData(t, map[string]string{"sv_SE/word": `["only-mine"]`, "greeting": `["hej"]`})
+	f, err := New(WithDataPath(dir), WithSeed(1))
+	if err != nil {
+		t.Fatalf("New = %v", err)
+	}
+	if got := fake(t, f, "sv_SE.word"); got != "only-mine" {
+		t.Errorf("sv_SE.word = %q, want the layered file to win", got)
+	}
+	if got := fake(t, f, "sv_SE.person"); got == "" {
+		t.Error("sv_SE.person should still come from the shipped data")
+	}
+	if got := fake(t, f, "greeting"); got != "hej" {
+		t.Errorf("greeting = %q, want hej", got)
+	}
+}
+
+func TestUserDataMayReferenceShipped(t *testing.T) {
+	dir := writeData(t, map[string]string{"greeting": `{"format":"Hej {..sv_SE.person}!"}`})
+	f, err := New(WithDataPath(dir), WithSeed(1))
+	if err != nil {
+		t.Fatalf("New = %v", err)
+	}
+	if got := fake(t, f, "greeting"); !strings.HasPrefix(got, "Hej ") || !strings.HasSuffix(got, "!") {
+		t.Errorf("greeting = %q", got)
+	}
+}
+
+func TestWithoutShippedDataNeedsASource(t *testing.T) {
+	_, err := New(WithoutShippedData())
+	if err == nil || !strings.Contains(err.Error(), "WithDataPath") {
+		t.Fatalf("New(WithoutShippedData()) = %v, want an error naming WithDataPath", err)
+	}
+}
+
+func TestWithoutShippedDataListsOnlyOwn(t *testing.T) {
+	dir := writeData(t, map[string]string{"greeting": `["hej"]`})
+	f := newGenerator(t, dir, WithSeed(1))
+	if got := f.List(); !reflect.DeepEqual(got, []string{"greeting"}) {
+		t.Errorf("List() = %v, want only the loaded dir", got)
+	}
+}
+
+func TestWithDataFS(t *testing.T) {
+	fsys := fstest.MapFS{
+		"greeting.json":  {Data: []byte(`["hej"]`)},
+		"nested/x.json":  {Data: []byte(`{"format":"{y}","y":["z"]}`)},
+		".hidden.json":   {Data: []byte(`["ignored"]`)},
+		"broken/no.json": {Data: []byte(`["x"]`)},
+	}
+	f, err := New(WithoutShippedData(), WithDataFS(fsys), WithSeed(1))
+	if err != nil {
+		t.Fatalf("New(WithDataFS) = %v", err)
+	}
+	if got := fake(t, f, "greeting"); got != "hej" {
+		t.Errorf("greeting = %q, want hej", got)
+	}
+	if got := fake(t, f, "nested.x.y"); got != "z" {
+		t.Errorf("nested.x.y = %q, want z", got)
+	}
+	bad := fstest.MapFS{"broken.json": {Data: []byte(`{ not json`)}}
+	if _, err := New(WithoutShippedData(), WithDataFS(bad)); err == nil || !strings.Contains(err.Error(), "broken.json") {
+		t.Errorf("New(bad fs) = %v, want an error naming the file", err)
+	}
+}
+
+func TestFakeIsSafeForConcurrentUse(t *testing.T) {
+	f, err := New(WithSeed(1))
+	if err != nil {
+		t.Fatal(err)
+	}
+	var wg sync.WaitGroup
+	for g := 0; g < 8; g++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for i := 0; i < 200; i++ {
+				if _, err := f.Fake("sv_SE.person"); err != nil {
+					t.Error(err)
+					return
+				}
+				f.List()
+			}
+		}()
+	}
+	wg.Wait()
+}