(new) added assert.inDelta

vowsjs · Jun 28, 2011 · bc868fa · bc868fa
1 parent 5b770a4
commit bc868fa
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Showing 2 changed files with 19 additions and 3 deletions.
diff --git a/lib/assert/macros.js b/lib/assert/macros.js
@@ -61,6 +61,14 @@ assert.lesser = function (actual, expected, message) {
     }
 };
 
+assert.inDelta = function (actual, expected, delta, message) {
+    lower = expected - delta;
+    upper = expected + delta;
+    if (actual < lower || actual > upper) {
+        assert.fail(actual, expected, message || "expected {actual} to be in within *"+ delta.toString() +"* of {expected}", null, assert.inDelta);
+    }
+};
+
 //
 // Inclusion
 //

diff --git a/test/assert-test.js b/test/assert-test.js
@@ -90,6 +90,13 @@ vows.describe('vows/assert').addBatch({
             assert.greater(5, 4);
             assert.lesser(4, 5);
         },
+        "`inDelta`": function (assert) {
+            assert.inDelta(42, 40, 5);
+            assert.inDelta(42, 40, 2);
+            assert.inDelta(42, 42, 0);
+            assert.inDelta(3.1, 3.0, 0.2);
+            assertError(assert.inDelta, [42, 40, 1]);
+        },
         "`isEmpty`": function (assert) {
             assert.isEmpty({});
             assert.isEmpty([]);
@@ -98,13 +105,14 @@ vows.describe('vows/assert').addBatch({
     }
 }).export(module);
 
-function assertError(assertion, value, fail) {
+function assertError(assertion, args, fail) {
+    if (!Array.isArray(args)) { args = [args]; }
     try {
-        assertion(value);
+        assertion.apply(null, args);
         fail = true;
     } catch (e) {/* Success */}
 
-    fail && assert.fail(value, assert.AssertionError, 
+    fail && assert.fail(args.join(' '), assert.AssertionError,
                                "expected an AssertionError for {actual}",
                                "assertError", assertError);
 }