diff --git a/test/js/group-player.js b/test/js/group-player.js
index 7bceab7..1237252 100644
--- a/test/js/group-player.js
+++ b/test/js/group-player.js
@@ -12,6 +12,10 @@ suite('group-player', function() {
           ],
           500);
     };
+
+    // FIXME: Remove. Used for testing pause on simple Animations during dev of this test.
+    this.animationMargin = animationMargin;
+
     var animationColor = function(target) {
       return new Animation(
           target,
@@ -21,7 +25,6 @@ suite('group-player', function() {
           ],
           500);
     };
-
     var sequenceEmpty = function() {
       return new AnimationSequence();
     };
@@ -254,6 +257,54 @@ suite('group-player', function() {
     assert.equal(getComputedStyle(this.complexTarget).marginLeft, '0px');
   });
 
+  test('redundant animation node wrapping', function() {
+    var target = document.createElement('div');
+    document.documentElement.appendChild(target);
+    function createAnimation(value, duration) {
+      return new Animation(target, [{marginLeft: value}, {marginLeft: value}], duration);
+    }
+    tick(100);
+    var animation = new AnimationSequence([
+      createAnimation('0px', 1),
+      new AnimationGroup([
+        new AnimationSequence([
+          createAnimation('1px', 1),
+          createAnimation('2px', 1),
+        ]),
+      ]),
+    ]);
+    var player = document.timeline.play(animation);
+    assert.equal(getComputedStyle(target).marginLeft, '0px');
+    checkTimes(player, [100, 0], [
+      [100, 0, 0, 0], [[ // 0
+        [101, -1, 0, 1], // 1
+        [102, -2, 1, 2]]] // 2
+    ], 't = 100');
+    tick(101);
+    assert.equal(getComputedStyle(target).marginLeft, '1px');
+    checkTimes(player, [100, 1], [
+      [100, 1, 0, 0], [[ // 0
+        [101, 0, 0, 1], // 1
+        [102, -1, 1, 2]]] // 2
+    ], 't = 101');
+    tick(102);
+    assert.equal(getComputedStyle(target).marginLeft, '2px');
+    assert.equal(document.timeline.currentTime, 102);
+    checkTimes(player, [100, 2], [ // FIXME: Implement limiting on group players
+      [100, 1, 0, 0], [[ // 0
+        [101, 1, 0, 1], // 1
+        [102, 0, 1, 2]]] // 2
+    ], 't = 102');
+    tick(103);
+    assert.equal(getComputedStyle(target).marginLeft, '0px');
+    checkTimes(player, [100, 3], [ // FIXME: Implement limiting on group players
+      [100, 1, 0, 0], [[ // 0
+        [101, 1, 0, 1], // 1
+        [102, 1, 1, 2]]] // 2
+    ], 't = 103');
+    target.remove();
+  });
+
   // FIXME: This test can be removed when this suite is finished.
   test('sources are working for basic operations', function() {
     var players = [];
@@ -316,51 +367,323 @@ suite('group-player', function() {
       players[i].play();
   });
 
-  test('redundant animation node wrapping', function() {
+  test('pausing works as expected with an empty AnimationSequence', function() {
+    tick(0);
+    var player = document.timeline.play(this.seqEmpty_source);
+    // check: player
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    player.pause();
+    // check
+  });
+
+  test('pausing works as expected with a simple AnimationSequence', function() {
+    tick(0);
+    var player = document.timeline.play(this.seqSimple_source);
+    // check: player,
+    //        player.childPlayers[0],
+    //        player.childPlayers[1]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[1].currentTime, X);
+    tick(200);
+    // check
+    player.pause();
+    // check
+    tick(300);
+    // check
+    player.play();
+    tick(300);
+    // check
+    tick(700);
+    // check
+  });
+
+  test('pausing works as expected with an AnimationSequence inside an AnimationSequence', function() {
+    tick(0);
+    var player = document.timeline.play(this.seqWithSeq_source);
+    // check: player,
+    //        player.childPlayers[0],
+    //        player.childPlayers[1],
+    //        player.childPlayers[2],
+    //        player.childPlayers[2].childPlayers[0],
+    //        player.childPlayers[2].childPlayers[1]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[1].currentTime, X);
+    // assert.equal(player.childPlayers[2].startTime, X);
+    // assert.equal(player.childPlayers[2].currentTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[1].currentTime, X);
+    tick(200);
+    // check
+    player.pause();
+    // check
+    tick(300);
+    // check
+    player.play();
+    tick(300);
+    // check
+    tick(1300);
+    // check
+    player.pause();
+    // check
+    tick(1400);
+    // check
+    player.play();
+    tick(1400);
+    // check
+    tick(1600);
+    // check
+    player.pause();
+    // check
+    tick(1700);
+    // check
+    player.play();
+    tick(1700);
+    // check
+  });
+
+  test('pausing works as expected with an AnimationGroup inside an AnimationSequence', function() {
+    tick(0);
+    var player = document.timeline.play(this.seqWithGroup_source);
+    // check: player,
+    //        player.childPlayers[0],
+    //        player.childPlayers[1],
+    //        player.childPlayers[2],
+    //        player.childPlayers[2].childPlayers[0],
+    //        player.childPlayers[2].childPlayers[1]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[1].currentTime, X);
+    // assert.equal(player.childPlayers[2].startTime, X);
+    // assert.equal(player.childPlayers[2].currentTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[1].currentTime, X);
+    tick(200);
+    // check
+    player.pause();
+    // check
+    tick(300);
+    // check
+    player.play();
+    tick(300);
+    // check
+    tick(1300);
+    // check
+    player.pause();
+    // check
+    tick(1400);
+    // check
+    player.play();
+    tick(1400);
+    // check
+  });
+
+  test('pausing works as expected with an empty AnimationSequence inside an AnimationSequence', function() {
+    tick(0);
+    var player = document.timeline.play(this.seqWithEmptySeq_source);
+    // check: player,
+    //        player.childPlayers[0]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    player.pause();
+    // check
+  });
+
+  test('pausing works as expected with an empty AnimationGroup inside an AnimationSequence', function() {
+    tick(0);
+    var player = document.timeline.play(this.seqWithEmptyGroup_source);
+    // check: player,
+    //        player.childPlayers[0]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    player.pause();
+    // check
+  });
+
+  test('pausing works as expected with an empty AnimationGroup', function() {
+    tick(0);
+    var player = document.timeline.play(this.groupEmpty_source);
+    // check: player
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    player.pause();
+    // check
+  });
+
+  test('pausing works as expected with a simple AnimationGroup', function() {
+    tick(0);
+    console.log(this.groupSimple_source);
+    var player = document.timeline.play(this.groupSimple_source);
+    // check: player,
+    //        player.childPlayers[0],
+    //        player.childPlayers[1]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[1].currentTime, X);
+    tick(200);
+    // check
+    player.pause();
+    // check
+    tick(300);
+    // check
+    player.play();
+    tick(300);
+    // check
+  });
+
+  test('pausing works as expected with an AnimationSequence inside an AnimationGroup', function() {
+    tick(0);
+    var player = document.timeline.play(this.groupWithSeq_source);
+    // check: player,
+    //        player.childPlayers[0],
+    //        player.childPlayers[1],
+    //        player.childPlayers[2],
+    //        player.childPlayers[2].childPlayers[0],
+    //        player.childPlayers[2].childPlayers[1]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[1].currentTime, X);
+    // assert.equal(player.childPlayers[2].startTime, X);
+    // assert.equal(player.childPlayers[2].currentTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[1].currentTime, X);
+    tick(200);
+    // check
+    player.pause();
+    // check
+    tick(300);
+    // check
+    player.play();
+    tick(300);
+    // check
+    tick(800);
+    // check
+    player.pause();
+    // check
+    tick(900);
+    // check
+    player.play();
+    tick(900);
+    // check
+    tick(1300);
+    // check
+    player.pause();
+    // check
+    tick(1300);
+    // check
+    player.play();
+    tick(1400);
+    // check
+  });
+
+  test('pausing works as expected with an AnimationGroup inside an AnimationGroup', function() {
+    tick(0);
+    var player = document.timeline.play(this.groupWithGroup_source);
+    // check: player,
+    //        player.childPlayers[0],
+    //        player.childPlayers[1],
+    //        player.childPlayers[2],
+    //        player.childPlayers[2].childPlayers[0],
+    //        player.childPlayers[2].childPlayers[1]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[1].currentTime, X);
+    // assert.equal(player.childPlayers[2].startTime, X);
+    // assert.equal(player.childPlayers[2].currentTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[0].currentTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[1].startTime, X);
+    // assert.equal(player.childPlayers[2].childPlayers[1].currentTime, X);
+    tick(200);
+    // check
+    player.pause();
+    // check
+    tick(300);
+    // check
+    player.play();
+    tick(300);
+    // check
+  });
+
+  test('pausing works as expected with an empty AnimationSequence inside an AnimationGroup', function() {
+    tick(0);
+    var player = document.timeline.play(this.groupWithEmptySeq_source);
+    // check: player,
+    //        player.childPlayers[0]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    player.pause();
+    // check
+  });
+
+  test('pausing works as expected with an empty AnimationGroup inside an AnimationGroup', function() {
+    tick(0);
+    var player = document.timeline.play(this.groupWithEmptyGroup_source);
+    // check: player,
+    //        player.childPlayers[0]
+    // assert.equal(player.startTime, X);
+    // assert.equal(player.currentTime, X);
+    // assert.equal(player.childPlayers[0].startTime, X);
+    // assert.equal(player.childPlayers[0].currentTime, X);
+    player.pause();
+    // check
+  });
+
+  // FIXME: This is just here as a baseline during development. REMOVE.
+  test('pausing works as expected with a simple Animation', function() {
+    tick(0);
     var target = document.createElement('div');
-    document.documentElement.appendChild(target);
-    function createAnimation(value, duration) {
-      return new Animation(target, [{marginLeft: value}, {marginLeft: value}], duration);
-    }
-    tick(100);
-    var animation = new AnimationSequence([
-      createAnimation('0px', 1),
-      new AnimationGroup([
-        new AnimationSequence([
-          createAnimation('1px', 1),
-          createAnimation('2px', 1),
-        ]),
-      ]),
-    ]);
-    var player = document.timeline.play(animation);
-    assert.equal(getComputedStyle(target).marginLeft, '0px');
-    checkTimes(player, [100, 0], [
-      [100, 0, 0, 0], [[ // 0
-        [101, -1, 0, 1], // 1
-        [102, -2, 1, 2]]] // 2
-    ], 't = 100');
-    tick(101);
-    assert.equal(getComputedStyle(target).marginLeft, '1px');
-    checkTimes(player, [100, 1], [
-      [100, 1, 0, 0], [[ // 0
-        [101, 0, 0, 1], // 1
-        [102, -1, 1, 2]]] // 2
-    ], 't = 101');
-    tick(102);
-    assert.equal(getComputedStyle(target).marginLeft, '2px');
-    assert.equal(document.timeline.currentTime, 102);
-    checkTimes(player, [100, 2], [ // FIXME: Implement limiting on group players
-      [100, 1, 0, 0], [[ // 0
-        [101, 1, 0, 1], // 1
-        [102, 0, 1, 2]]] // 2
-    ], 't = 102');
-    tick(103);
-    assert.equal(getComputedStyle(target).marginLeft, '0px');
-    checkTimes(player, [100, 3], [ // FIXME: Implement limiting on group players
-      [100, 1, 0, 0], [[ // 0
-        [101, 1, 0, 1], // 1
-        [102, 1, 1, 2]]] // 2
-    ], 't = 103');
-    target.remove();
+    var player = document.timeline.play(this.animationMargin(target));
+    assert.equal(player.startTime, 0);
+    assert.equal(player.currentTime, 0);
+    tick(200);
+    assert.equal(player.startTime, 0);
+    assert.equal(player.currentTime, 200);
+    player.pause();
+    assert.equal(player.startTime, null);
+    assert.equal(player.currentTime, 200);
+    tick(300);
+    assert.equal(player.startTime, null);
+    assert.equal(player.currentTime, 200);
+    player.play();
+    tick(300);
+    assert.equal(player.startTime, 100);
+    assert.equal(player.currentTime, 200);
+    tick(600);
+    setTicking(true);
+    assert.equal(player.startTime, 100);
+    assert.equal(player.currentTime, 500);
   });
 });