1 files changed, 86 insertions, 0 deletions
diff --git a/comm/mailnews/mime/jsmime/test/unit/mock_date.js b/comm/mailnews/mime/jsmime/test/unit/mock_date.js
new file mode 100644
index 0000000000..87a6454968
--- /dev/null
+++ b/comm/mailnews/mime/jsmime/test/unit/mock_date.js
@@ -0,0 +1,86 @@
+"use strict";
+
+/* globals define */
+
+define(function (require) {
+  /**
+   * A class which appears to act like the Date class with customizable timezone
+   * offsets.
+   *
+   * @param {string} iso8601String An ISO-8601 date/time string including a
+   *                               timezone offset.
+   */
+  function MockDate(iso8601String) {
+    // Find the timezone offset (Z or ±hhmm) from the ISO-8601 date string, and
+    // then convert that into a number of minutes.
+    let parse = /\d{4}-\d\d-\d\dT\d\d:\d\d:\d\d(Z|[+-]\d{4})/.exec(
+      iso8601String
+    );
+    let tzOffsetStr = parse[1];
+    if (tzOffsetStr == "Z") {
+      this._tzOffset = 0;
+    } else {
+      this._tzOffset =
+        parseInt(tzOffsetStr.substring(1, 3)) * 60 +
+        parseInt(tzOffsetStr.substring(3));
+      if (tzOffsetStr[0] == "-") {
+        this._tzOffset = -this._tzOffset;
+      }
+    }
+
+    // To store the offset, we store both the real time in _realDate and a time
+    // that is offset by the tzOffset in _shiftedDate. Only the getUTC* methods
+    // should be used on these properties, to avoid problems caused by daylight
+    // savings time or other timezone effects. This shifting is always legal
+    // because ES6 is specified to assume that leap seconds do not exist, so there
+    // are always 60 seconds in a minute.
+    this._realDate = new Date(iso8601String);
+    this._shiftedDate = new Date(
+      this._realDate.getTime() + this._tzOffset * 60 * 1000
+    );
+  }
+  MockDate.prototype = {
+    getTimezoneOffset() {
+      // This property is reversed from how it's defined in ISO 8601, i.e.,
+      // UTC +0100 needs to return -60.
+      return -this._tzOffset;
+    },
+    getTime() {
+      return this._realDate.getTime();
+    },
+  };
+
+  // Provide an implementation of Date methods that will be need in JSMime. For
+  // the time being, we only need .get* methods.
+  for (let name of Object.getOwnPropertyNames(Date.prototype)) {
+    // Only copy getters, not setters or x.toString.
+    if (!name.startsWith("get")) {
+      continue;
+    }
+    // No redefining any other names on MockDate.
+    if (MockDate.prototype.hasOwnProperty(name)) {
+      continue;
+    }
+
+    if (name.includes("UTC")) {
+      // 'name' is already supposed to be freshly bound per newest ES6 drafts, but
+      // current ES6 implementations reuse the bindings. Until implementations
+      // catch up, use a new let to bind it freshly.
+      let boundName = name;
+      Object.defineProperty(MockDate.prototype, name, {
+        value(...aArgs) {
+          return Date.prototype[boundName].call(this._realDate, aArgs);
+        },
+      });
+    } else {
+      let newName = "getUTC" + name.substr(3);
+      Object.defineProperty(MockDate.prototype, name, {
+        value(...aArgs) {
+          return Date.prototype[newName].call(this._shiftedDate, aArgs);
+        },
+      });
+    }
+  }
+
+  return MockDate;
+});