Merge branch 'smallyard-master'

Author: sbrannen

junit-platform-commons/src/main/java/org/junit/platform/commons/util/StringUtils.java

@@ -81,7 +81,9 @@ public static String nullSafeToString(Class<?>... classes) {
 	 * Generate a comma-separated list of mapped values for the supplied classes.
 	 *
 	 * <p>The values are generated by the supplied {@code mapper}
-	 * (e.g., {@code Class::getName}, {@code Class::getSimpleName}, etc.).
+	 * (e.g., {@code Class::getName}, {@code Class::getSimpleName}, etc.), unless
+	 * a class reference is {@code null} in which case it will be mapped to
+	 * {@code "null"}.
 	 *
 	 * @param mapper the mapper to use
 	 * @param classes the classes to map
@@ -93,7 +95,7 @@ public static String nullSafeToString(Function<? super Class<?>, ? extends Strin
 		if (classes == null || classes.length == 0) {
 			return "";
 		}
-		return stream(classes).map(mapper).collect(joining(", "));
+		return stream(classes).map(v -> v == null ? "null" : mapper.apply(v)).collect(joining(", "));
 	}
 
 }

platform-tests/src/test/java/org/junit/platform/commons/util/StringUtilsTests.java

@@ -36,6 +36,8 @@ void nullSafeToString() {
 		assertEquals("", StringUtils.nullSafeToString());
 		assertEquals("java.lang.String", StringUtils.nullSafeToString(String.class));
 		assertEquals("java.lang.String, java.lang.Integer", StringUtils.nullSafeToString(String.class, Integer.class));
+		assertEquals("java.lang.String, null, java.lang.Integer",
+			StringUtils.nullSafeToString(String.class, null, Integer.class));
 	}
 
 }