Bug 1690631 - Add string matching helpers to Assert.jsm r=Gijs

This adds Assert.stringContains and Assert.stringMatches.

Differential Revision: https://phabricator.services.mozilla.com/D104254

testing/modules/Assert.jsm

@@ -424,7 +424,7 @@ function expectedException(actual, expected) {
  *
  * @param block
  *        (function) Function block to evaluate and catch eventual thrown errors
- * @param expected (optional)
+ * @param expected
  *        (mixed) This parameter can be either a RegExp or a function. The
  *        function is either the error type's constructor, or it's a method that returns a boolean
  *        that describes the test outcome.
@@ -596,3 +596,81 @@ proto.less = function less(lhs, rhs, message) {
 proto.lessOrEqual = function lessOrEqual(lhs, rhs, message) {
   compareNumbers.call(this, lhs > rhs, lhs, rhs, message, "<=");
 };
+
+/**
+ * The lhs must be a string that matches the rhs regular expression.
+ * rhs can be specified either as a string or a RegExp object. If specified as a
+ * string it will be interpreted as a regular expression so take care to escape
+ * special characters such as "?" or "(" if you need the actual characters.
+ *
+ * @param lhs
+ *        (string) The string to be tested.
+ * @param rhs
+ *        (string | RegExp) The regular expression that the string will be
+ *        tested with. Note that if passed as a string, this will be interpreted
+ *        as a regular expression.
+ * @param message (optional)
+ *        (string) Short explanation of the comparison result
+ */
+proto.stringMatches = function stringMatches(lhs, rhs, message) {
+  if (typeof rhs != "string" && !instanceOf(rhs, "RegExp")) {
+    this.report(
+      true,
+      lhs,
+      String(rhs),
+      `Expected a string or a RegExp for rhs, but "${rhs}" isn't a string or a RegExp object.`
+    );
+    return;
+  }
+
+  if (typeof lhs != "string") {
+    this.report(
+      true,
+      lhs,
+      String(rhs),
+      `Expected a string for lhs, but "${lhs}" isn't a string.`
+    );
+    return;
+  }
+
+  if (typeof rhs == "string") {
+    try {
+      rhs = new RegExp(rhs);
+    } catch {
+      this.report(
+        true,
+        lhs,
+        rhs,
+        `Expected a valid regular expression for rhs, but "${rhs}" isn't one.`
+      );
+      return;
+    }
+  }
+
+  const isCorrect = rhs.test(lhs);
+  this.report(!isCorrect, lhs, rhs.toString(), message, "matches");
+};
+
+/**
+ * The lhs must be a string that contains the rhs string.
+ *
+ * @param lhs
+ *        (string) The string to be tested.
+ * @param rhs
+ *        (string) The string to be found.
+ * @param message (optional)
+ *        (string) Short explanation of the comparison result
+ */
+proto.stringContains = function stringContains(lhs, rhs, message) {
+  if (typeof lhs != "string" || typeof rhs != "string") {
+    this.report(
+      true,
+      lhs,
+      rhs,
+      `Expected a string for both lhs and rhs, but either "${lhs}" or "${rhs}" is not a string.`
+    );
+  }
+
+  const isCorrect = lhs.includes(rhs);
+  this.report(!isCorrect, lhs, rhs, message, "includes");
+};

testing/modules/tests/browser/browser_test_assert.js

@@ -14,4 +14,8 @@ function test() {
 
   var func = is;
   func(1, 1, "pass indirect is");
+
+  stringMatches("hello world", /llo\s/);
+  stringMatches("hello world", "llo\\s");
+  stringContains("hello world", "llo");
 }

testing/modules/tests/xpcshell/test_assert.js

@@ -409,6 +409,29 @@ function run_test() {
   }
   assert.equal(message, "AssertionError: 2 <= 1");
 
+  /* ---- stringMatches ---- */
+  assert.stringMatches("hello world", /llo\s/);
+  assert.stringMatches("hello world", "llo\\s");
+  assert.throws(
+    () => assert.stringMatches("hello world", /foo/),
+    /^AssertionError: "hello world" matches "\/foo\/"/
+  );
+  assert.throws(
+    () => assert.stringMatches(5, /foo/),
+    /^AssertionError: Expected a string for lhs, but "5" isn't a string./
+  );
+  assert.throws(
+    () => assert.stringMatches("foo bar", "+"),
+    /^AssertionError: Expected a valid regular expression for rhs, but "\+" isn't one./
+  );
+
+  /* ---- stringContains ---- */
+  assert.stringContains("hello world", "llo");
+  assert.throws(
+    () => assert.stringContains(5, "foo"),
+    /^AssertionError: Expected a string for both lhs and rhs, but either "5" or "foo" is not a string./
+  );
+
   run_next_test();
 }
 

tools/lint/eslint/eslint-plugin-mozilla/lib/configs/browser-test.js

@@ -45,6 +45,8 @@ module.exports = {
     registerCleanupFunction: false,
     requestLongerTimeout: false,
     setExpectedFailuresForSelfTest: false,
+    stringContains: false,
+    stringMatches: false,
     todo: false,
     todo_is: false,
     todo_isnot: false,