add PercentEscaperTest

google-http-client/src/main/java/com/google/api/client/util/escape/CharEscapers.java

@@ -16,7 +16,6 @@
 
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
-import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 
 /**

google-http-client/src/test/java/com/google/api/client/util/escape/PercentEscaperTest.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.google.api.client.util.escape;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class PercentEscaperTest {
+
+  @Test
+  public void testEscapeSpace() {
+    PercentEscaper escaper =
+        new PercentEscaper(PercentEscaper.SAFE_PLUS_RESERVED_CHARS_URLENCODER, false);
+    String actual = escaper.escape("Hello there");
+    Assert.assertEquals("Hello%20there", actual);
+  }
+}