test: add test for unknown variable

Author: javier-godoy

src/test/java/com/flowingcode/vaadin/addons/demo/it/ConditionalSourceCodeViewerIT.java

@@ -51,4 +51,9 @@ public void testConditionElif() {
   public void testConditionNested() {
     assertEquals(expected(), open(VAADIN_VERSION));
   }
+
+  @Test
+  public void testConditionUnknownVariable() {
+    assertEquals(expected(), open(VAADIN_VERSION));
+  }
 }

src/test/resources/com/flowingcode/vaadin/addons/demo/it/ConditionUnknownVariable.java

@@ -0,0 +1,10 @@
+class MyClass {
+  // show-source begin
+  // #if unknown eq 42
+  // show-source eq
+  // #endif
+  // #if unknown ne 42
+  // show-source ne
+  // #endif
+  // show-source end
+}

src/test/resources/com/flowingcode/vaadin/addons/demo/it/ConditionUnknownVariable.txt

@@ -0,0 +1,4 @@
+class MyClass {
+  begin
+  end
+}