09-reducer-testing complete

src/app/shared/state/__snapshots__/books.reducer.spec.ts.snap

@@ -0,0 +1,41 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Books Reducer should add a newly created book to the state 1`] = `
+Object {
+  "activeBookId": "1",
+  "entities": Object {
+    "1": Object {
+      "earnings": 200000000,
+      "id": "1",
+      "name": "Forrest Gump",
+    },
+  },
+  "ids": Array [
+    "1",
+  ],
+}
+`;
+
+exports[`Books Reducer should load all books when the API loads them all successfully 1`] = `
+Object {
+  "activeBookId": null,
+  "entities": Object {
+    "1": Object {
+      "earnings": 1000000,
+      "id": "1",
+      "name": "Castaway",
+    },
+  },
+  "ids": Array [
+    "1",
+  ],
+}
+`;
+
+exports[`Books Reducer should remove books from the state when they are deleted 1`] = `
+Object {
+  "activeBookId": null,
+  "entities": Object {},
+  "ids": Array [],
+}
+`;

src/app/shared/state/books.reducer.spec.ts

@@ -1,7 +1,80 @@
-// import { BooksApiActions, BooksPageActions } from "src/app/books/actions";
-// import { Book } from "../models/book.model";
-// import { reducer, initialState } from "./book.reducer";
+import { BooksApiActions, BooksPageActions } from "src/app/books/actions";
+import { Book } from "../models/book.model";
+import {
+  reducer,
+  initialState,
+  selectActiveBook,
+  adapter,
+  selectAll
+} from "./books.reducer";
 
 describe("Books Reducer", () => {
-  it("should return the initial state when initialized", () => {});
+  it("should return the initial state when initialized", () => {
+    const state = reducer(undefined, { type: "@@init" } as any);
+
+    expect(state).toBe(initialState);
+  });
+
+  it("should load all books when the API loads them all successfully", () => {
+    const books: Book[] = [{ id: "1", name: "Castaway", earnings: 1000000 }];
+    const action = BooksApiActions.booksLoaded({ books });
+
+    const state = reducer(initialState, action);
+
+    expect(state).toMatchSnapshot();
+  });
+
+  it("should add a newly created book to the state", () => {
+    const book: Book = { id: "1", name: "Forrest Gump", earnings: 200000000 };
+    const action = BooksApiActions.bookCreated({ book });
+
+    const state = reducer(initialState, action);
+
+    expect(state).toMatchSnapshot();
+  });
+
+  it("should remove books from the state when they are deleted", () => {
+    const book: Book = { id: "1", name: "Apollo 13", earnings: 1000 };
+    const firstAction = BooksApiActions.bookCreated({ book });
+    const secondAction = BooksApiActions.bookDeleted({ book });
+
+    const state = [firstAction, secondAction].reduce(reducer, initialState);
+
+    expect(state).toMatchSnapshot();
+  });
+
+  describe("Selectors", () => {
+    const initialState = { activeBookId: null, ids: [], entities: {} };
+
+    describe("selectActiveBook", () => {
+      it("should return null if there is no active book", () => {
+        const result = selectActiveBook(initialState);
+
+        expect(result).toBe(null);
+      });
+
+      it("should return the active book if there is one", () => {
+        const book: Book = { id: "1", name: "Castaway", earnings: 1000000 };
+        const state = adapter.addAll([book], {
+          ...initialState,
+          activeBookId: "1"
+        });
+        const result = selectActiveBook(state);
+
+        expect(result).toBe(book);
+      });
+    });
+
+    describe("selectAll", () => {
+      it("should return all the loaded books", () => {
+        const books: Book[] = [
+          { id: "1", name: "Castaway", earnings: 1000000 }
+        ];
+        const state = adapter.addAll(books, initialState);
+        const result = selectAll(state);
+
+        expect(result.length).toBe(1);
+      });
+    });
+  });
 });