Refactored code: moved method containsOnlyExtProperties to AbstractTe…

…xtAssert enhances spring-iogh-1348

initializr-generator-test/src/main/java/io/spring/initializr/generator/test/buildsystem/gradle/GroovyDslGradleBuildAssert.java

@@ -85,21 +85,4 @@ public GroovyDslGradleBuildAssert hasProperty(String name, String value) {
 		return contains(String.format("%s = '%s'", name, value));
 	}
 
-	/**
-	 * Assert {@code build.gradle} contains only the specified properties.
-	 * @param values the property value pairs
-	 * @return this for method chaining.
-	 */
-	public GroovyDslGradleBuildAssert containsOnlyExtProperties(String... values) {
-		StringBuilder builder = new StringBuilder(String.format("ext {%n"));
-		if (values.length % 2 == 1) {
-			throw new IllegalArgumentException("Size must be even, it is a set of property=value pairs");
-		}
-		for (int i = 0; i < values.length; i += 2) {
-			builder.append(String.format("\tset('%s', \"%s\")%n", values[i], values[i + 1]));
-		}
-		builder.append("}");
-		return contains(builder.toString());
-	}
-
 }