more passing tests

test/map.js

@@ -1,11 +1,36 @@
 var concatMap = require('../');
 var test = require('tap').test;
 
-test('concat mapping', function (t) {
+test('empty or not', function (t) {
     var xs = [ 1, 2, 3, 4, 5, 6 ];
     var ys = concatMap(xs, function (x) {
         return x % 2 ? [ x - 0.1, x, x + 0.1 ] : [];
     });
     t.same(ys, [ 0.9, 1, 1.1, 2.9, 3, 3.1, 4.9, 5, 5.1 ]);
     t.end();
 });
+
+test('always something', function (t) {
+    var xs = [ 'a', 'b', 'c', 'd' ];
+    var ys = concatMap(xs, function (x) {
+        return x === 'b' ? [ 'B', 'B', 'B' ] : [ x ];
+    });
+    t.same(ys, [ 'a', 'B', 'B', 'B', 'c', 'd' ]);
+    t.end();
+});
+
+test('scalars', function (t) {
+    var xs = [ 'a', 'b', 'c', 'd' ];
+    var ys = concatMap(xs, function (x) {
+        return x === 'b' ? [ 'B', 'B', 'B' ] : x;
+    });
+    t.same(ys, [ 'a', 'B', 'B', 'B', 'c', 'd' ]);
+    t.end();
+});
+
+test('undefs', function (t) {
+    var xs = [ 'a', 'b', 'c', 'd' ];
+    var ys = concatMap(xs, function () {});
+    t.same(ys, [ undefined, undefined, undefined, undefined ]);
+    t.end();
+});