diff --git a/src/test/java/com/pivovarit/gatherers/blackbox/WindowSlidingTest.java b/src/test/java/com/pivovarit/gatherers/blackbox/WindowSlidingTest.java
index 8403612..35a3838 100644
--- a/src/test/java/com/pivovarit/gatherers/blackbox/WindowSlidingTest.java
+++ b/src/test/java/com/pivovarit/gatherers/blackbox/WindowSlidingTest.java
@@ -25,11 +25,24 @@ void shouldRejectInvalidStep() {
           .hasMessage("'step' must be greater than or equal to zero");
     }
 
+    @Test
+    void shouldRejectInvalidWindowSizeAndStep() {
+        assertThatThrownBy(() -> MoreGatherers.windowSliding(3, 4))
+          .isInstanceOf(IllegalArgumentException.class)
+          .hasMessage("'step' must be less than or equal to 'windowSize'");
+    }
+
     @Test
     void shouldWindowSlidingEmpty() {
         assertThat(Stream.empty().gather(MoreGatherers.windowSliding(2, 1))).isEmpty();
     }
 
+    @Test
+    void shouldWindowSlidingWithWindowSizeGreaterThanStreamSize() {
+        assertThat(Stream.of(1, 2, 3).gather(MoreGatherers.windowSliding(4, 1)))
+          .containsExactly(of(1, 2, 3));
+    }
+
     @Test
     void shouldWindowSlidingWithStep1() {
         assertThat(Stream.of(1, 2, 3, 4, 5).gather(MoreGatherers.windowSliding(2, 1)))