first batch of generic assert tests

js/utils.js

@@ -412,4 +412,101 @@ async function hardReload() {
 
 function capitalizeFirst(str) {
     return str[0].toUpperCase() + str.substring(1);
-}
+}
+
+/** https://stackoverflow.com/questions/16839698/jquery-getscript-alternative-in-native-javascript
+ *  If we ever want to write something that needs to import other js files
+ */
+ const getScript = url => new Promise((resolve, reject) => {
+    const script = document.createElement('script')
+    script.src = url
+    script.async = true
+  
+    script.onerror = reject
+  
+    script.onload = script.onreadystatechange = function() {
+      const loadState = this.readyState
+  
+      if (loadState && loadState !== 'loaded' && loadState !== 'complete') return
+  
+      script.onload = script.onreadystatechange = null
+  
+      resolve()
+    }
+  
+    document.head.appendChild(script)
+  })
+
+/* 
+GENERIC TEST FUNCTIONS
+*/
+/** The generic assert function. Fails on all "false-y" values. Useful for non-object equality checks, boolean value checks, and existence checks.
+ * 
+ * @param {*} arg - argument to assert.
+ * @param {String} msg - the error message to throw. 
+ */
+ function assert(arg, msg) {
+    if (!arg) {
+        throw new Error(msg ? msg : "Assert failed.");
+    }
+}
+
+/** Asserts object equality of the 2 parameters. For loose and strict asserts, use assert().
+ * 
+ * @param {*} arg1 - first argument to compare.
+ * @param {*} arg2 - second argument to compare.
+ * @param {String} msg - the error message to throw. 
+ */
+function assert_equals(arg1, arg2, msg) {
+    if (!Object.is(arg1, arg2)) {
+        throw new Error(msg ? msg : "Assert Equals failed. " + arg1 + " is not " + arg2 + ".");
+    }
+}
+
+/** Asserts object inequality of the 2 parameters. For loose and strict asserts, use assert().
+ * 
+ * @param {*} arg1 - first argument to compare.
+ * @param {*} arg2 - second argument to compare.
+ * @param {String} msg - the error message to throw. 
+ */
+ function assert_not_equals(arg1, arg2, msg) {
+    if (Object.is(arg1, arg2)) {
+        throw new Error(msg ? msg : "Assert Not Equals failed. " + arg1 + " is " + arg2 + ".");
+    }
+}
+
+/** Asserts proximity between 2 arguments. Should be used for any floating point datatype.
+ * 
+ * @param {*} arg1 - first argument to compare.
+ * @param {*} arg2 - second argument to compare.
+ * @param {Number} epsilon - the margin of error (<= del difference is ok).
+ * @param {String} msg - the error message to throw. 
+ */
+function assert_near(arg1, arg2, epsilon, msg) {
+    if (Math.abs(arg1 - arg2) > epsilon) {
+        throw new Error(msg ? msg : "Assert Near failed. " + arg1 + " is not within " + epsilon + " of " + arg2 + ".");
+    }
+}
+
+/** Asserts that the input argument is null.
+ * 
+ * @param {*} arg - the argument to test for null.
+ * @param {String} msg - the error message to throw.
+ */
+function assert_null(arg, msg) {
+    if (arg !== null) {
+        throw new Error(msg ? msg : "Assert Near failed. " + arg + " is not null.");
+    }
+}
+
+/** Asserts that the input argument is undefined.
+ * 
+ * @param {*} arg - the argument to test for undefined.
+ * @param {String} msg - the error message to throw.
+ */
+ function assert_undefined(arg, msg) {
+    if (arg !== undefined) {
+        throw new Error(msg ? msg : "Assert Near failed. " + arg + " is not undefined.");
+    }
+}
+