Add post image storage

internal/store/post_test.go

@@ -267,6 +267,93 @@ func TestMemoryPostValidation(t *testing.T) {
 	}
 }
 
+func TestMemoryPostImages(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.Background()
+	mem := NewMemory()
+	homeowner := &User{Username: "images", PasswordHash: "hash", Role: RoleUser}
+	if err := mem.CreateUser(ctx, homeowner); err != nil {
+		t.Fatal(err)
+	}
+	root := &Post{
+		ID:       "image-root",
+		AuthorID: homeowner.ID,
+		Title:    "What is leaking?",
+		Body:     "Here are two photos.",
+		Images: []PostImage{
+			{ID: "image-a", ObjectKey: "posts/image-root/image-a.jpg", PublicURL: "https://cdn.example/image-a.jpg", Description: "  Supply valve  ", Position: 3, Width: 1200, Height: 900},
+			{ID: "image-b", ObjectKey: "posts/image-root/image-b.png", PublicURL: "https://cdn.example/image-b.png", Width: 900, Height: 1200},
+		},
+	}
+	if err := mem.CreatePost(ctx, root); err != nil {
+		t.Fatal(err)
+	}
+	if root.Images[0].Position != 0 ||
+		root.Images[1].Position != 1 ||
+		root.Images[0].PostID != root.ID ||
+		root.Images[0].Description != "Supply valve" {
+		t.Fatalf("created images were not normalized: %+v", root.Images)
+	}
+
+	loaded, err := mem.GetPost(ctx, root.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	loaded.Images[0].Description = "mutated outside store"
+	reloaded, err := mem.GetPost(ctx, root.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if reloaded.Images[0].Description != "Supply valve" {
+		t.Fatalf("stored image mutated through clone: %+v", reloaded.Images[0])
+	}
+
+	reloaded.Body = "Updated photos."
+	reloaded.Images = []PostImage{
+		reloaded.Images[1],
+		{ID: "image-c", ObjectKey: "posts/image-root/image-c.jpg", PublicURL: "https://cdn.example/image-c.jpg", Description: "Trap connection", Width: 1600, Height: 1000},
+	}
+	if err := mem.UpdatePost(ctx, reloaded); err != nil {
+		t.Fatal(err)
+	}
+	updated, err := mem.GetPost(ctx, root.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(updated.Images) != 2 ||
+		updated.Images[0].ID != "image-b" ||
+		updated.Images[0].Position != 0 ||
+		updated.Images[1].ID != "image-c" ||
+		updated.Images[1].Position != 1 {
+		t.Fatalf("updated images = %+v", updated.Images)
+	}
+
+	tooMany := &Post{
+		AuthorID: homeowner.ID,
+		Title:    "Too many",
+		Body:     "Five photos.",
+		Images:   validPostImages(5),
+	}
+	if err := mem.CreatePost(ctx, tooMany); !errors.Is(err, ErrInvalidPost) {
+		t.Fatalf("five-image create error = %v, want ErrInvalidPost", err)
+	}
+}
+
+func validPostImages(count int) []PostImage {
+	images := make([]PostImage, count)
+	for i := range images {
+		images[i] = PostImage{
+			ID:        "image-" + string(rune('a'+i)),
+			ObjectKey: "posts/key-" + string(rune('a'+i)) + ".jpg",
+			PublicURL: "https://cdn.example/" + string(rune('a'+i)) + ".jpg",
+			Width:     100,
+			Height:    100,
+		}
+	}
+	return images
+}
+
 func ptr(value string) *string {
 	return &value
 }