tests: added test for fetchTopLanguages

tests/fetchTopLanguages.test.js

@@ -0,0 +1,84 @@
+require("@testing-library/jest-dom");
+const axios = require("axios");
+const MockAdapter = require("axios-mock-adapter");
+const fetchTopLanguages = require("../src/fetchTopLanguages");
+
+const mock = new MockAdapter(axios);
+
+afterEach(() => {
+  mock.reset();
+});
+
+const data_langs = {
+  data: {
+    user: {
+      repositories: {
+        nodes: [
+          {
+            languages: {
+              edges: [{ size: 100, node: { color: "#0f0", name: "HTML" } }],
+            },
+          },
+          {
+            languages: {
+              edges: [{ size: 100, node: { color: "#0f0", name: "HTML" } }],
+            },
+          },
+          {
+            languages: {
+              edges: [
+                { size: 100, node: { color: "#0ff", name: "javascript" } },
+              ],
+            },
+          },
+          {
+            languages: {
+              edges: [
+                { size: 100, node: { color: "#0ff", name: "javascript" } },
+              ],
+            },
+          },
+        ],
+      },
+    },
+  },
+};
+
+const error = {
+  errors: [
+    {
+      type: "NOT_FOUND",
+      path: ["user"],
+      locations: [],
+      message: "Could not resolve to a User with the login of 'noname'.",
+    },
+  ],
+};
+
+describe("FetchTopLanguages", () => {
+  it("should fetch correct language data", async () => {
+    mock.onPost("https://api.github.com/graphql").reply(200, data_langs);
+
+    let repo = await fetchTopLanguages("anuraghazra");
+    expect(repo).toStrictEqual({
+      HTML: {
+        color: "#0f0",
+        name: "HTML",
+        size: 200,
+      },
+      javascript: {
+        color: "#0ff",
+        name: "javascript",
+        size: 200,
+      },
+    });
+  });
+
+  it("should throw error", async () => {
+    mock.onPost("https://api.github.com/graphql").reply(200, error);
+
+    await expect(fetchTopLanguages("anuraghazra")).rejects.toThrow(
+      "Could not resolve to a User with the login of 'noname'."
+    );
+  });
+});