diff --git a/packages/ember-debug/lib/handlers.js b/packages/ember-debug/lib/handlers.js
index dc82e9cb956..7d7fbef1a6a 100644
--- a/packages/ember-debug/lib/handlers.js
+++ b/packages/ember-debug/lib/handlers.js
@@ -1,28 +1,5 @@
-import isPlainFunction from 'ember-debug/is-plain-function';
-import deprecate from 'ember-debug/deprecate';
-
 export let HANDLERS = { };
 
-export function generateTestAsFunctionDeprecation(source) {
-  return `Calling \`${source}\` with a function argument is deprecated. Please ` +
-    `use \`!!Constructor\` for constructors, or an \`IIFE\` to compute the test for deprecation. ` +
-    `In a future version, functions will be treated as truthy values instead of being executed.`;
-}
-
-function normalizeTest(test, source) {
-  if (isPlainFunction(test)) {
-    deprecate(
-      generateTestAsFunctionDeprecation(source),
-      false,
-      { id: 'ember-debug.deprecate-test-as-function', until: '2.5.0' }
-    );
-
-    return test();
-  }
-
-  return test;
-}
-
 export function registerHandler(type, callback) {
   let nextHandler = HANDLERS[type] || function() { };
 
@@ -32,7 +9,7 @@ export function registerHandler(type, callback) {
 }
 
 export function invoke(type, message, test, options) {
-  if (normalizeTest(test, 'Ember.' + type)) { return; }
+  if (test) { return; }
 
   let handlerForType = HANDLERS[type];
 
diff --git a/packages/ember-debug/lib/index.js b/packages/ember-debug/lib/index.js
index 829ed035ce3..582cfd30898 100644
--- a/packages/ember-debug/lib/index.js
+++ b/packages/ember-debug/lib/index.js
@@ -15,8 +15,6 @@ import _deprecate, {
 import _warn, {
   registerHandler as registerWarnHandler
 } from 'ember-debug/warn';
-import isPlainFunction from 'ember-debug/is-plain-function';
-import { generateTestAsFunctionDeprecation } from 'ember-debug/handlers';
 
 /**
 @module ember
@@ -51,21 +49,7 @@ import { generateTestAsFunctionDeprecation } from 'ember-debug/handlers';
   @public
 */
 setDebugFunction('assert', function assert(desc, test) {
-  let throwAssertion;
-
-  if (isPlainFunction(test)) {
-    deprecate(
-      generateTestAsFunctionDeprecation('Ember.assert'),
-      false,
-      { id: 'ember-debug.deprecate-test-as-function', until: '2.5.0' }
-    );
-
-    throwAssertion = !test();
-  } else {
-    throwAssertion = !test;
-  }
-
-  if (throwAssertion) {
+  if (!test) {
     throw new EmberError('Assertion Failed: ' + desc);
   }
 });
diff --git a/packages/ember-debug/lib/is-plain-function.js b/packages/ember-debug/lib/is-plain-function.js
deleted file mode 100644
index 925741604e3..00000000000
--- a/packages/ember-debug/lib/is-plain-function.js
+++ /dev/null
@@ -1,3 +0,0 @@
-export default function isPlainFunction(test) {
-  return typeof test === 'function' && test.PrototypeMixin === undefined;
-}
diff --git a/packages/ember-debug/tests/main_test.js b/packages/ember-debug/tests/main_test.js
index 693a70c8308..c5d09ceb2b6 100644
--- a/packages/ember-debug/tests/main_test.js
+++ b/packages/ember-debug/tests/main_test.js
@@ -1,6 +1,6 @@
 import Ember from 'ember-metal/core';
 import EmberObject from 'ember-runtime/system/object';
-import { HANDLERS, generateTestAsFunctionDeprecation } from 'ember-debug/handlers';
+import { HANDLERS } from 'ember-debug/handlers';
 import {
   registerHandler,
   missingOptionsDeprecation,
@@ -13,7 +13,6 @@ import {
   missingOptionsDeprecation as missingWarnOptionsDeprecation,
   registerHandler as registerWarnHandler
 } from 'ember-debug/warn';
-import deprecate from 'ember-debug/deprecate';
 
 let originalEnvValue;
 let originalDeprecateHandler;
@@ -107,21 +106,14 @@ QUnit.test('Ember.deprecate throws deprecation if second argument is falsy', fun
   });
 });
 
-QUnit.test('Ember.deprecate throws deprecation if second argument is a function and it returns true', function(assert) {
-  assert.expect(1);
+QUnit.test('Ember.deprecate does not invoke a function as the second argument', function() {
+  expect(1);
 
-  throws(() => {
-    Ember.deprecate('This deprecation is not thrown, but argument deprecation is thrown', () => true, { id: 'test', until: 'forever' });
-  });
-});
+  Ember.deprecate('Deprecation is thrown', function() {
+    ok(false, 'this function should not be invoked');
+  }, { id: 'test', until: 'forever' });
 
-QUnit.test('Ember.deprecate throws if second argument is a function and it returns false', function() {
-  expect(1);
-  throws(function() {
-    Ember.deprecate('Deprecation is thrown', function() {
-      return false;
-    }, { id: 'test', until: 'forever' });
-  });
+  ok(true, 'deprecations were not thrown');
 });
 
 QUnit.test('Ember.deprecate does not throw deprecations if second argument is truthy', function() {
@@ -150,23 +142,12 @@ QUnit.test('Ember.assert throws if second argument is falsy', function() {
   });
 });
 
-QUnit.test('Ember.assert does not throw if second argument is a function and it returns true', function(assert) {
+QUnit.test('Ember.assert does not throw if second argument is a function', function(assert) {
   assert.expect(1);
 
-  // Shouldn't trigger an assertion, but deprecation from using function as test is expected.
-  expectDeprecation(
-    () => Ember.assert('Assertion is thrown', () => true),
-    generateTestAsFunctionDeprecation('Ember.assert')
-  );
-});
+  Ember.assert('Assertion is thrown', () => true);
 
-QUnit.test('Ember.assert throws if second argument is a function and it returns false', function() {
-  expect(1);
-  throws(function() {
-    Ember.assert('Assertion is thrown', function() {
-      return false;
-    });
-  });
+  ok(true, 'assertions were not thrown');
 });
 
 QUnit.test('Ember.assert does not throw if second argument is truthy', function() {
@@ -298,39 +279,3 @@ QUnit.test('Ember.warn without options.id triggers a deprecation', function(asse
 
   Ember.warn('foo', false, { });
 });
-
-QUnit.test('Ember.deprecate triggers a deprecation when test argument is a function', function(assert) {
-  assert.expect(1);
-
-  registerHandler(message => assert.equal(
-    message,
-    generateTestAsFunctionDeprecation('Ember.deprecate'),
-    'proper deprecation is triggered when test argument is a function'
-  ));
-
-  deprecate('Deprecation is thrown', () => true, { id: 'test', until: 'forever' });
-});
-
-QUnit.test('Ember.warn triggers a deprecation when test argument is a function', function(assert) {
-  assert.expect(1);
-
-  registerHandler(message => assert.equal(
-    message,
-    generateTestAsFunctionDeprecation('Ember.warn'),
-    'proper deprecation is triggered when test argument is a function'
-  ));
-
-  Ember.warn('Warning is thrown', () => true, { id: 'test' });
-});
-
-QUnit.test('Ember.assert triggers a deprecation when test argument is a function', function(assert) {
-  assert.expect(1);
-
-  registerHandler(message => assert.equal(
-    message,
-    generateTestAsFunctionDeprecation('Ember.assert'),
-    'proper deprecation is triggered when test argument is a function'
-  ));
-
-  Ember.assert('Assertion is thrown', () => true);
-});