diff --git a/tests/domain/world-settings.command.test.ts b/tests/domain/world-settings.command.test.ts
new file mode 100644
index 00000000..5b69baef
--- /dev/null
+++ b/tests/domain/world-settings.command.test.ts
@@ -0,0 +1,33 @@
+import { describe, expect, it } from "vitest";
+
+import { createEditorStore } from "../../src/app/editor-store";
+import { createSetWorldSettingsCommand } from "../../src/commands/set-world-settings-command";
+import { createEmptySceneDocument } from "../../src/document/scene-document";
+import { cloneWorldSettings } from "../../src/document/world-settings";
+
+describe("createSetWorldSettingsCommand", () => {
+  it("updates authored world settings and restores them through undo", () => {
+    const store = createEditorStore();
+    const originalWorld = cloneWorldSettings(store.getState().document.world);
+    const nextWorld = cloneWorldSettings(originalWorld);
+
+    nextWorld.background = {
+      mode: "verticalGradient",
+      topColorHex: "#6e8db4",
+      bottomColorHex: "#18212b"
+    };
+    nextWorld.ambientLight.intensity = 0.45;
+
+    store.executeCommand(
+      createSetWorldSettingsCommand({
+        label: "Set world lighting",
+        world: nextWorld
+      })
+    );
+
+    expect(store.getState().document.world).toEqual(nextWorld);
+
+    expect(store.undo()).toBe(true);
+    expect(store.getState().document.world).toEqual(createEmptySceneDocument().world);
+  });
+});
diff --git a/tests/domain/world-settings.test.ts b/tests/domain/world-settings.test.ts
new file mode 100644
index 00000000..1fc8da7d
--- /dev/null
+++ b/tests/domain/world-settings.test.ts
@@ -0,0 +1,43 @@
+import { describe, expect, it } from "vitest";
+
+import { createDefaultWorldSettings } from "../../src/document/scene-document";
+import { areWorldSettingsEqual, changeWorldBackgroundMode, cloneWorldSettings } from "../../src/document/world-settings";
+
+describe("world settings helpers", () => {
+  it("clones world settings without retaining nested references", () => {
+    const source = createDefaultWorldSettings();
+    const clone = cloneWorldSettings(source);
+
+    expect(clone).toEqual(source);
+    expect(clone).not.toBe(source);
+    expect(clone.background).not.toBe(source.background);
+    expect(clone.sunLight.direction).not.toBe(source.sunLight.direction);
+  });
+
+  it("switches a solid background into a gradient while preserving the authored color as the top edge", () => {
+    const gradient = changeWorldBackgroundMode(
+      {
+        mode: "solid",
+        colorHex: "#334455"
+      },
+      "verticalGradient"
+    );
+
+    expect(gradient).toEqual({
+      mode: "verticalGradient",
+      topColorHex: "#334455",
+      bottomColorHex: "#141a22"
+    });
+  });
+
+  it("compares authored world settings by value", () => {
+    const left = createDefaultWorldSettings();
+    const right = cloneWorldSettings(left);
+
+    expect(areWorldSettingsEqual(left, right)).toBe(true);
+
+    right.sunLight.direction.x = right.sunLight.direction.x + 0.25;
+
+    expect(areWorldSettingsEqual(left, right)).toBe(false);
+  });
+});