Infer sign of range's step when only start and end are provided.

lodash.js

@@ -13282,11 +13282,10 @@
       if (end === undefined) {
         end = start;
         start = 0;
-        step = step === undefined ? (start < end ? 1 : -1) : step;
       } else {
         end = toNumber(end) || 0;
       }
-      step = step === undefined ? 1 : (toNumber(step) || 0);
+      step = step === undefined ? (start < end ? 1 : -1) : (toNumber(step) || 0);
 
       var n = nativeMax(nativeCeil((end - start) / (step || 1)), 0);
       return baseTimes(n, function(index) {

test/test.js

@@ -15555,27 +15555,25 @@
   QUnit.module('lodash.range');
 
   (function() {
-    QUnit.test('should work with only an `end` argument', function(assert) {
-      assert.expect(1);
+    QUnit.test('should infer the sign of `step` when provided only an `end` argument', function(assert) {
+      assert.expect(2);
 
       assert.deepEqual(_.range(4), [0, 1, 2, 3]);
-    });
-
-    QUnit.test('should use a `step` of `-1` when provided only a negative `end` argument', function(assert) {
-      assert.expect(1);
-
       assert.deepEqual(_.range(-4), [0, -1, -2, -3]);
     });
 
-    QUnit.test('should work with `start` and `end` arguments', function(assert) {
-      assert.expect(1);
+    QUnit.test('should infer the sign of `step` when provided only a `start` and `end` argument', function(assert) {
+      assert.expect(2);
 
       assert.deepEqual(_.range(1, 5), [1, 2, 3, 4]);
+      assert.deepEqual(_.range(5, 1), [5, 4, 3, 2]);
     });
 
     QUnit.test('should work with `start`, `end`, and `step` arguments', function(assert) {
-      assert.expect(1);
+      assert.expect(3);
 
+      assert.deepEqual(_.range(0, -4, -1), [0, -1, -2, -3]);
+      assert.deepEqual(_.range(5, 1, -1), [5, 4, 3, 2]);
       assert.deepEqual(_.range(0, 20, 5), [0, 5, 10, 15]);
     });
 

test/underscore.html

@@ -77,6 +77,9 @@
             'an array of pairs zipped together into an object',
             'an object converted to pairs and back to an object'
           ],
+          'range': [
+            'range with two arguments a & b, b<a generates an empty array'
+          ],
           'rest': [
             'working rest(0)',
             'rest can take an index',