diff --git a/tests/unit/viewport-view-modes.test.ts b/tests/unit/viewport-view-modes.test.ts
new file mode 100644
index 00000000..fbe7f42d
--- /dev/null
+++ b/tests/unit/viewport-view-modes.test.ts
@@ -0,0 +1,71 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  getViewportViewModeControlHint,
+  getViewportViewModeDefinition,
+  getViewportViewModeGridPlaneLabel,
+  getViewportViewModeLabel
+} from "../../src/viewport-three/viewport-view-modes";
+
+describe("viewport view modes", () => {
+  it("defines the orthographic axes and grid planes explicitly", () => {
+    expect(getViewportViewModeDefinition("top")).toMatchObject({
+      label: "Top",
+      cameraType: "orthographic",
+      cameraDirection: {
+        x: 0,
+        y: 1,
+        z: 0
+      },
+      cameraUp: {
+        x: 0,
+        y: 0,
+        z: -1
+      },
+      gridPlane: "xz",
+      snapAxis: "y"
+    });
+
+    expect(getViewportViewModeDefinition("front")).toMatchObject({
+      label: "Front",
+      cameraType: "orthographic",
+      cameraDirection: {
+        x: 0,
+        y: 0,
+        z: 1
+      },
+      cameraUp: {
+        x: 0,
+        y: 1,
+        z: 0
+      },
+      gridPlane: "xy",
+      snapAxis: "z"
+    });
+
+    expect(getViewportViewModeDefinition("side")).toMatchObject({
+      label: "Side",
+      cameraType: "orthographic",
+      cameraDirection: {
+        x: -1,
+        y: 0,
+        z: 0
+      },
+      cameraUp: {
+        x: 0,
+        y: 1,
+        z: 0
+      },
+      gridPlane: "yz",
+      snapAxis: "x"
+    });
+  });
+
+  it("exposes readable labels and grid hints for the UI", () => {
+    expect(getViewportViewModeLabel("perspective")).toBe("Perspective");
+    expect(getViewportViewModeLabel("top")).toBe("Top");
+    expect(getViewportViewModeGridPlaneLabel("front")).toBe("XY");
+    expect(getViewportViewModeControlHint("perspective")).toContain("orbits");
+    expect(getViewportViewModeControlHint("side")).toContain("pans");
+  });
+});