#33 FromArray.any_match + unit tests

lib/fromarray.rb

@@ -101,7 +101,8 @@ def skip(count)
     # given predicate (a function which performs a test on the value and
     # should return a boolean).
     #
-    # If the stream is empty, the returned value is true.
+    # If the stream is empty, the returned value is true and the predicate
+    # is not called at all.
     #
     # This is a terminal operation.
     # +test+:: A function which should perform some boolean test on the
@@ -113,6 +114,24 @@ def all_match(&test)
       true
     end
 
+    # Returns true if any of the elements of the Stream are matching
+    # the given predicate (a function which performs a test on the value and
+    # should return a boolean). Iteration will stop at the first match.
+    #
+    # If the stream is empty, the returned value is false and the predicate
+    # is not called at all.
+    #
+    # This is a terminal operation.
+    #
+    # +test+:: A function which should perform some boolean test on the
+    #  given value.
+    def any_match(&test)
+      @array.each do |val|
+        return true if test.call(val)
+      end
+      false
+    end
+
     # Collect the stream's data into an array and return it.
     # This is a terminal operation.
     def collect

test/fromarray_test.rb

@@ -258,5 +258,33 @@ def test_not_all_elements_match
         'Expected false because not all elements are a match!'
       )
     end
+
+    # FromArray.any_match returns true if one element matches.
+    def test_any_element_matches
+      stream = FromArray.new([2, 4, 6, 8])
+      assert(
+        stream.any_match { |val| val == 4 },
+        'Stream contains element 4, it should match!'
+      )
+    end
+
+    # FromArray.any_match returns true if all elements match.
+    def test_any_match_all
+      stream = FromArray.new([2, 4, 6, 8])
+      assert(
+        stream.any_match { |val| val %2 == 0 },
+        'All elements are even, it should match!'
+      )
+    end
+
+    # FromArray.any_match returns false and the predicate is never called,
+    # because the stream is empty.
+    def test_any_match_empty
+      stream = FromArray.new([])
+      assert(
+        !stream.any_match { raise ScriptError, 'Should not be called' },
+        'Stream is empty, any_match should be false!'
+      )
+    end
   end
 end