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bin/observable/index.test.ts

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+import { Observable } from "./observable";
+import { getCollectionItems } from "./utils";
+
+describe("observable", () => {
+  it("should be able to create an observable", async () => {
+    const observable = new Observable(() => Promise.resolve(1));
+    expect(observable).toBeDefined();
+    const data = await observable.data;
+    expect(data).toBe(1);
+  });
+
+  it("should be able to combine observables", async () => {
+    const observable1 = new Observable(() => Promise.resolve(1));
+    const observable2 = new Observable(() => Promise.resolve(2));
+    const combined = Observable.combine({ observable1, observable2 });
+    const data = await combined.data;
+    expect(data.observable1).toBe(1);
+    expect(data.observable2).toBe(2);
+  });
+
+  it("should be able to update observable", async () => {
+    const observable = new Observable(() => Promise.resolve(1));
+    const data = await observable.data;
+    expect(data).toBe(1);
+    observable.set(() => Promise.resolve(2));
+    const data2 = await observable.data;
+    expect(data2).toBe(2);
+  });
+
+  it("should be able to extract collection items", async () => {
+    const observable = new Observable(() =>
+      Promise.resolve([
+        new Observable(() => Promise.resolve(1)),
+        new Observable(() => Promise.resolve(2)),
+        new Observable(() => Promise.resolve(3)),
+      ])
+    );
+    const flatten = observable.pipe(getCollectionItems);
+    const data = await flatten.data;
+    expect(data).toEqual([1, 2, 3]);
+  });
+
+  it("should update observable when subscribed", async () => {
+    const observable = new Observable(() => Promise.resolve(1));
+    const spy = jest.fn();
+    observable.subscribe(spy);
+    expect(spy).not.toHaveBeenCalled();
+    observable.set(() => Promise.resolve(2));
+    expect(spy).toHaveBeenCalled();
+    expect(spy).toHaveBeenCalledTimes(1);
+  });
+
+  it("should update combined observable when subscribed", async () => {
+    const observable1 = new Observable(() => Promise.resolve(1));
+    const observable2 = new Observable(() => Promise.resolve(2));
+    const combined = Observable.combine({ observable1, observable2 });
+    const spy = jest.fn();
+    const data1 = await combined.data;
+    expect(data1.observable1).toBe(1);
+    expect(data1.observable2).toBe(2);
+    combined.subscribe(spy);
+    expect(spy).not.toHaveBeenCalled();
+    observable2.set(() => Promise.resolve(3));
+    expect(spy).toHaveBeenCalled();
+    expect(spy).toHaveBeenCalledTimes(1);
+    const data2 = await combined.data;
+    expect(data2.observable1).toBe(1);
+    expect(data2.observable2).toBe(3);
+  });
+});