From 07bcf762d01abb0972e3358d3e327bce5326d79c Mon Sep 17 00:00:00 2001
From: Colin Caine <cmc@cs.man.ac.uk>
Date: Thu, 5 Oct 2017 03:42:55 +0100
Subject: [PATCH] tests: Update and fix example tests

---
 src/mod.test.ts | 66 +++++++++++++++++++++++++++++++++----------------
 1 file changed, 45 insertions(+), 21 deletions(-)

diff --git a/src/mod.test.ts b/src/mod.test.ts
index 0c5c6074..5eb0139f 100644
--- a/src/mod.test.ts
+++ b/src/mod.test.ts
@@ -1,42 +1,66 @@
-import {euclid_mod, knuth_mod, my_mod, koushien_mod} from './number.mod'
+/** Some real tests for mod and also an example of how to unit test. */
 
+import {euclid_mod, knuth_mod, my_mod} from './number.mod'
+
+expect.extend({
+    /** Expect equal to all values in array */
+    toBeAll(received, values:Array<any>) {
+        for (let val of values) {
+            if (received !== val) {
+                return {
+                    message: () => `expected ${received} === for each v in ${values}`,
+                    pass: false
+                }
+            }
+        }
+        return {
+            message: () => `expected ${received} !== for some v in ${values}`,
+            pass: true
+        }
+    }
+})
+
+/** Manually written tests */
 const testcases = [
-	[-3, 3, 0],
-	[-2, 3, 1],
-	[-1, 3, 2],
-	[0, 3, 0],
-	[1, 3, 1],
-	[2, 3, 2],
-	[3, 3, 0],
-	[4, 3, 1],
-	[5, 3, 2],
-	[6, 3, 0],
-
-    /* [-5, -4, 0] */
+    [-3, 3, 0],
+    [-2, 3, 1],
+    [-1, 3, 2],
+    [0, 3, 0],
+    [1, 3, 1],
+    [2, 3, 2],
+    [3, 3, 0],
+    [4, 3, 1],
+    [5, 3, 2],
+    [6, 3, 0],
 ]
 
-function assert(value) {
-    return expect(value).toEqual(true)
-}
-
 for (let [a, b, ans] of testcases) {
-    /* test(`${a}.mod(${b}) === ${ans}, ${a.mod(b)}`, ()=>expect(a.mod(b) === ans).toEqual(true)) */
-    /* test(`${a} (mod ${b})`, ()=>expect(a.mod(b)).toEqual(ans)) */
+    test(`${a} (mod ${b}) -- .mod`, ()=>expect(a.mod(b)).toEqual(ans))
     test(`${a} (mod ${b}) -- euclid`, ()=>expect(euclid_mod(a, b)).toEqual(ans))
     test(`${a} (mod ${b}) -- knuth`, ()=>expect(knuth_mod(a, b)).toEqual(ans))
     test(`${a} (mod ${b}) -- my`, ()=>expect(my_mod(a, b)).toEqual(ans))
 }
 
 
+/** Test with mixed dividend, positive divisor */
 for (let i=0; i<1000; i++) {
     let a = (Math.random()-0.5) * 10000|0
     let b = Math.random() * 10000|0
-    test(`${a} (mod ${b}) -- equivalence check`, () => expect(knuth_mod(a,b)).toEqual(my_mod(a,b)).toEqual(koushien_mod(a,b)))
+    b = b === 0 ? 17 : b // Don't be 0.
+    test(`${a} (mod ${b}) -- equivalence check`, () => expect(a.mod(b)).toBeAll([
+        my_mod(a,b),
+        euclid_mod(a,b),
+        knuth_mod(a,b),
+    ]))
 }
 
 /** Test with a mix of +ve and -ve */
 for (let i=0; i<1000; i++) {
     let a = (Math.random()-0.5) * 10000|0
     let b = (Math.random()-0.5) * 10000|0
-    test(`${a} (mod ${b}) -- equivalence check`, () => expect(knuth_mod(a,b)).toEqual(koushien_mod(a,b)))
+    b = b === 0 ? 17 : b // Don't be 0.
+    test(`${a} (mod ${b}) -- equivalence check`, () => expect(a.mod(b)).toBeAll([
+        my_mod(a,b),
+        knuth_mod(a,b),
+    ]))
 }