refactored media rule test

tests/org.eclipse.e4.ui.tests.css.core/src/org/eclipse/e4/ui/tests/css/core/parser/MediaRulesTest.java

@@ -17,8 +17,8 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import java.util.List;
 import java.util.stream.IntStream;
+import java.util.stream.Stream;
 
 import org.eclipse.e4.ui.tests.css.core.util.ParserTestUtil;
 import org.junit.jupiter.api.Test;
@@ -40,12 +40,16 @@ void testMediaRule() throws Exception {
 				Label { background-color: #FF0000 }""";
 		CSSStyleSheet styleSheet = ParserTestUtil.parseCss(css);
 		assertNotNull(styleSheet);
-		List<String> cssRules = IntStream.range(0, styleSheet.getCssRules().getLength())
-				.mapToObj(i -> styleSheet.getCssRules().item(i).getCssText()).toList();
+		// This one is provided only inside the @media so it shouldn't be there
+		assertThat(findCssRuleThatContains(styleSheet, "background-color")).isEmpty();
+		// This one is provided outside the @media and it shouldn't be overwritten by
+		// any of them
+		assertThat(findCssRuleThatContains(styleSheet, "line-height")).containsOnly("BODY { line-height: 1.3; }");
+	}
 
-		assertThat(cssRules.stream().filter(it -> it.contains("background-color")).toList())
-		.containsOnly("Label { background-color: rgb(255, 0, 0); }");
-		assertThat(cssRules.stream().filter(it -> it.contains("line-height")).toList())
-				.containsOnly("BODY { line-height: 1.3; }");
+	private Stream<String> findCssRuleThatContains(CSSStyleSheet styleSheet, String text) {
+		Stream<String> cssRulesText = IntStream.range(0, styleSheet.getCssRules().getLength())
+				.mapToObj(i -> styleSheet.getCssRules().item(i).getCssText());
+		return cssRulesText.filter(r -> r.contains(text));
 	}
 }