Tests for transition.ease. #20

test/transition/ease-test.js

@@ -1,12 +1,74 @@
 var tape = require("tape"),
     jsdom = require("jsdom"),
-    d3 = require("d3-selection");
+    d3_ease = require("d3-ease"),
+    d3_timer = require("d3-timer"),
+    d3_selection = require("d3-selection");
 
 require("../../");
 
+tape("transition.ease() returns the easing function for the first non-null node", function(test) {
+  var document = jsdom.jsdom("<h1 id='one'></h1><h1 id='two'></h1>"),
+      one = document.querySelector("#one"),
+      two = document.querySelector("#two"),
+      transition1 = d3_selection.select(one).transition(),
+      transition2 = d3_selection.select(two).transition().ease(d3_ease.easeBounce);
+  test.strictEqual(one.__transition[transition1._id].ease, d3_ease.easeCubic);
+  test.strictEqual(two.__transition[transition2._id].ease, d3_ease.easeBounce);
+  test.strictEqual(transition1.ease(), d3_ease.easeCubic);
+  test.strictEqual(transition2.ease(), d3_ease.easeBounce);
+  test.strictEqual(d3_selection.select(one).transition(transition1).ease(), d3_ease.easeCubic);
+  test.strictEqual(d3_selection.select(two).transition(transition2).ease(), d3_ease.easeBounce);
+  test.strictEqual(d3_selection.selectAll([null, one]).transition(transition1).ease(), d3_ease.easeCubic);
+  test.strictEqual(d3_selection.selectAll([null, two]).transition(transition2).ease(), d3_ease.easeBounce);
+  test.strictEqual(d3_selection.selectAll([one, two]).transition(transition1).ease(), d3_ease.easeCubic);
+  test.strictEqual(d3_selection.selectAll([two, one]).transition(transition2).ease(), d3_ease.easeBounce);
+  test.end();
+});
+
 tape("transition.ease(ease) throws an error if ease is not a function", function(test) {
   var document = jsdom.jsdom(),
-      transition = d3.select(document.documentElement).transition();
+      transition = d3_selection.select(document.documentElement).transition();
   test.throws(function() { transition.ease(42); }, /Error/);
+  test.throws(function() { transition.ease(null); }, /Error/);
   test.end();
 });
+
+tape("transition.ease(ease) sets the easing function for each selected element to the specified function", function(test) {
+  var document = jsdom.jsdom("<h1 id='one'></h1><h1 id='two'></h1>"),
+      one = document.querySelector("#one"),
+      two = document.querySelector("#two"),
+      transition = d3_selection.selectAll([one, two]).transition().ease(d3_ease.easeBounce);
+  test.strictEqual(one.__transition[transition._id].ease, d3_ease.easeBounce);
+  test.strictEqual(two.__transition[transition._id].ease, d3_ease.easeBounce);
+  test.end();
+});
+
+tape("transition.ease(ease) passes the easing function the normalized time in [0, 1]", function(test) {
+  var root = jsdom.jsdom().documentElement,
+      actual,
+      ease = function(t) { actual = t; return t; },
+      transition = d3_selection.select(root).transition().ease(ease);
+
+  d3_timer.timeout(function(now) {
+    test.equal(actual, now / 250);
+    test.end();
+  }, 100);
+});
+
+tape("transition.ease(ease) does not invoke the easing function on the last frame", function(test) {
+  var root = jsdom.jsdom().documentElement,
+      ease = function(t) { test.equal(schedule.state, 3); return t; },
+      transition = d3_selection.select(root).transition().ease(ease).on("end", function() { test.end(); }),
+      schedule = root.__transition[transition._id];
+});
+
+tape("transition.ease(ease) observes the eased time returned by the easing function", function(test) {
+  var root = jsdom.jsdom().documentElement,
+      start = d3_timer.now(),
+      duration = 250,
+      expected,
+      ease = function() { return expected = Math.random() * 2 - 0.5; },
+      tween = function() { return function(t) { test.equal(t, schedule.state === 3 ? expected : 1); }; },
+      transition = d3_selection.select(root).transition().ease(ease).tween("tween", tween).on("end", function() { test.end(); }),
+      schedule = root.__transition[transition._id];
+});