Add first frontend tests for helpers.ts

frontend/leeds-beer-quest/src/tests/helpers.spec.ts

@@ -0,0 +1,43 @@
+import { ArrayToArrayUrlParams } from "../lib/helpers";
+import { expect, describe, it } from '@jest/globals';
+
+const exampleParamName = "testParamName";
+
+const exampleTestParams = ["one", "two", "three", "four", "five"];
+
+describe("Given the ArrayToArrayUrlParams function", () => {
+    describe("and the param array is empty", () => {
+        it("should return empty string", () => {
+            const paramResult = ArrayToArrayUrlParams("testParam", []);
+
+            expect(paramResult).toHaveLength(0);
+            expect(paramResult).toBe("");
+        });
+    });
+
+    describe("and the params are not the first in the param line", () => {
+        it("should return & as the first char, not ?", () => {
+            const paramResult = ArrayToArrayUrlParams("testParam", exampleTestParams, false);
+
+            expect(paramResult[0]).toBe("&");
+        });
+    });
+
+    describe("and the param array has values", () => {
+        it("should not return a string ending with &", () => {
+            const paramResult = ArrayToArrayUrlParams("testParam", exampleTestParams);
+
+            expect(paramResult[paramResult.length - 1]).not.toBe("&");
+        });
+
+        it.each([
+            [exampleTestParams, `?${exampleParamName}=${exampleTestParams[0]}&${exampleParamName}=${exampleTestParams[1]}&${exampleParamName}=${exampleTestParams[2]}&${exampleParamName}=${exampleTestParams[3]}&${exampleParamName}=${exampleTestParams[4]}`],
+            [["a", "b", "c"], `?${exampleParamName}=a&${exampleParamName}=b&${exampleParamName}=c`],
+            [["onlyParam"], `?${exampleParamName}=onlyParam`]
+        ])("should return a url parameter string with the included data", (params: string[], expectedResult: string) => {
+            const paramResult = ArrayToArrayUrlParams(exampleParamName, params);
+
+            expect(paramResult).toBe(expectedResult);
+        });
+    });
+});