#33 FromArray.all_match + unit tests

Author: amihaiemil

lib/fromarray.rb

@@ -26,6 +26,7 @@ module Stream
   # A stream implemented based on an Array.
   # This class is immutable and thread-safe.
   # Author:: Mihai Andronache ([email protected])
+  # Since:: 0.0.1
   class FromArray
     def initialize(array)
       @array = array
@@ -96,6 +97,22 @@ def skip(count)
       FromArray.new(skipped)
     end
 
+    # Returns true if all the elements of the Stream are matching the
+    # 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.
+    #
+    # This is a terminal operation.
+    # +test+:: A function which should perform some boolean test on the
+    #  given value.
+    def all_match(&test)
+      @array.each do |val|
+        return false unless test.call(val)
+      end
+      true
+    end
+
     # Collect the stream's data into an array and return it.
     # This is a terminal operation.
     def collect

test/fromarray_test.rb

@@ -229,5 +229,34 @@ def test_distinct_one_duplicate_element
       assert(collected.length == 1)
       assert(collected == collected.uniq)
     end
+
+    # FromArray.all_match returns true when all
+    # elements are a match.
+    def test_all_elements_match
+      stream = FromArray.new([2, 4, 6, 8])
+      assert(
+        stream.all_match { |val| val % 2 == 0 },
+        'All of the stream\'s elements should be even!'
+      )
+    end
+
+    # FromArray.all_match should return true if the stream is empty.
+    def test_all_match_no_elements
+      stream = FromArray.new([])
+      assert(
+        stream.all_match { |val| val % 2 == 1 },
+        'Expected true because the stream is empty!'
+      )
+    end
+
+    # FromArray.all_match returns false because not all the
+    # elements are a match
+    def test_not_all_elements_match
+      stream = FromArray.new([2, 4, 5, 6, 8])
+      assert(
+        stream.all_match { |val| val % 2 == 0 } == false,
+        'Expected false because not all elements are a match!'
+      )
+    end
   end
 end