Improve message of multi-type a/an assertions

chaijs · Sep 12, 2015 · d27ceb5 · d27ceb5
1 parent 5eb3906
commit d27ceb5
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Showing 3 changed files with 17 additions and 12 deletions.
diff --git a/lib/chai/core/assertions.js b/lib/chai/core/assertions.js
@@ -163,13 +163,18 @@ module.exports = function (chai, _) {
     if (msg) flag(this, 'message', msg);
     if (_.type(types) === 'string') types = [types];
     types = types.map(function (t) { return t.toLowerCase(); });
-    var obj = flag(this, 'object')
-      , article = ~[ 'a', 'e', 'i', 'o', 'u' ].indexOf(types[0].charAt(0)) ? 'an ' : 'a ';
+    var obj = flag(this, 'object');
+
+    var str = types.map(function (t, index) {
+      var art = ~[ 'a', 'e', 'i', 'o', 'u' ].indexOf(t.charAt(0)) ? 'an' : 'a';
+      var or = types.length > 1 && index === types.length - 1 ? 'or ' : '';
+      return or + art + ' ' + t;
+    }).join(', ');
 
     this.assert(
         types.some(function (expected) { return _.type(obj) === expected; })
-      , 'expected #{this} to be ' + article + types.join(', ')
-      , 'expected #{this} not to be ' + article + types.join(', ')
+      , 'expected #{this} to be ' + str
+      , 'expected #{this} not to be ' + str
     );
   }
 

diff --git a/test/expect.js b/test/expect.js
@@ -126,21 +126,21 @@ describe('expect', function () {
 
     err(function(){
       expect([]).to.be.a(['string', 'number', 'boolean']);
-    }, 'expected [] to be a string, number, boolean');
+    }, 'expected [] to be a string, a number, or a boolean');
 
     expect([]).to.not.be.a(['string', 'number', 'boolean']);
 
     err(function(){
       expect('foo').to.not.be.a(['string', 'number', 'boolean']);
-    }, 'expected \'foo\' not to be a string, number, boolean');
+    }, 'expected \'foo\' not to be a string, a number, or a boolean');
 
     err(function(){
       expect(42).to.not.be.a(['string', 'number', 'boolean']);
-    }, 'expected 42 not to be a string, number, boolean');
+    }, 'expected 42 not to be a string, a number, or a boolean');
 
     err(function(){
       expect(true).to.not.be.a(['string', 'number', 'boolean']);
-    }, 'expected true not to be a string, number, boolean');
+    }, 'expected true not to be a string, a number, or a boolean');
   });
 
   it('instanceof', function(){

diff --git a/test/should.js b/test/should.js
@@ -158,21 +158,21 @@ describe('should', function() {
 
     err(function(){
       [].should.be.a(['string', 'number', 'boolean']);
-    }, 'expected [] to be a string, number, boolean');
+    }, 'expected [] to be a string, a number, or a boolean');
 
     [].should.not.be.a(['string', 'number', 'boolean']);
 
     err(function(){
       'foo'.should.not.be.a(['string', 'number', 'boolean']);
-    }, 'expected \'foo\' not to be a string, number, boolean');
+    }, 'expected \'foo\' not to be a string, a number, or a boolean');
 
     err(function(){
       (42).should.not.be.a(['string', 'number', 'boolean']);
-    }, 'expected 42 not to be a string, number, boolean');
+    }, 'expected 42 not to be a string, a number, or a boolean');
 
     err(function(){
       (true).should.not.be.a(['string', 'number', 'boolean']);
-    }, 'expected true not to be a string, number, boolean');
+    }, 'expected true not to be a string, a number, or a boolean');
   });
 
   it('instanceof', function(){