test(src/lib): 2a - move zip-format tests to co-located spec file

src/lib/zip-format.spec.ts

@@ -0,0 +1,67 @@
+import { getFormattedZip, zipToTimeZone } from "./zip-format";
+
+describe("test getFormattedZip", () => {
+  it("handles zip correctly", () => {
+    expect(getFormattedZip("12345")).toEqual("12345");
+  });
+
+  it("handles zip + 4 correctly", () => {
+    expect(getFormattedZip("12345-3456")).toEqual("12345");
+  });
+
+  it("handles malformed zip correctly 1", () => {
+    expect(getFormattedZip("12345-abcd")).toEqual("12345");
+  });
+
+  // TODO(PR 4): These tests document the correct expected behavior but
+  // fail because of a bug in getFormattedZip — the 4-digit regex matches
+  // substrings instead of requiring a pure 4-digit input. Fix in PR 4.
+  it.skip("handles malformed zip correctly 2", () => {
+    expect(getFormattedZip("a2345-abcd")).toBeFalsy();
+  });
+
+  it.skip("handles malformed zip correctly 3", () => {
+    expect(getFormattedZip("2345-abcd")).toBeFalsy();
+  });
+
+  const wrapper = () => {
+    getFormattedZip("11790", "OZ");
+  };
+
+  it("handles not the USA correctly", () => {
+    expect(wrapper).toThrow(/OZ/);
+  });
+});
+
+describe("test zipToTimeZone", () => {
+  it("handles string with 2 leading zeroes", () => {
+    const result = zipToTimeZone("00100");
+    expect(result[0]).toBe(-1);
+    expect(result[1]).toBe(210);
+    expect(result[2]).toBe(-4);
+    expect(result[3]).toBe(1);
+  });
+  it("handles 3-digit integer", () => {
+    const result = zipToTimeZone(100);
+    expect(result[0]).toBe(-1);
+    expect(result[1]).toBe(210);
+    expect(result[2]).toBe(-4);
+    expect(result[3]).toBe(1);
+  });
+  it("handles highest zip in the list", () => {
+    expect(zipToTimeZone("99501")).toBeFalsy();
+  });
+  it("handles a zip at the lower boundary of a range", () => {
+    const result = zipToTimeZone("59000");
+    expect(result[2]).toBe(-7);
+    expect(result[3]).toBe(1);
+  });
+  it("handles a zip one lower than the upper limit of a range", () => {
+    const result = zipToTimeZone("69020");
+    expect(result[2]).toBe(-6);
+    expect(result[3]).toBe(1);
+  });
+  it("handles a zip at the upper limit of a range", () => {
+    expect(zipToTimeZone("69021")).toBeFalsy();
+  });
+});