Github user lfrancke commented on a diff in the pull request:
https://github.com/apache/nifi/pull/2872#discussion_r201485489
--- Diff:
nifi-testharness/src/main/java/org/apache/nifi/testharness/TestNiFiInstance.java
---
@@ -0,0 +1,485 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.nifi.testharness;
+
+import org.apache.nifi.testharness.api.FlowFileEditorCallback;
+import org.apache.nifi.EmbeddedNiFi;
+import org.apache.nifi.testharness.util.FileUtils;
+import org.apache.nifi.testharness.util.NiFiCoreLibClassLoader;
+import org.apache.nifi.testharness.util.XmlUtils;
+import org.apache.nifi.testharness.util.Zip;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.Set;
+import java.util.zip.ZipEntry;
+
+/**
+ * <p>
+ * An API wrapper of a "test" NiFi instance to which a flow definition is
installed for testing.</p>
+ *
+ * <p>
+ * Due to NiFi design restrictions, {@code TestNiFiInstance} has to take
<i>full command</i>
+ * of the current working directory: it installs a full NiFi installation
to there. To ensure
+ * this is desired, <strong>it will only run if the current directory is
called
+ * "nifi_testharness_nifi_home"</strong>. As such the JVM process has to
be started inside a directory
+ * called "nifi_testharness_nifi_home" so that the following is true:
+ *
+ * <pre><tt>
+ * new
File(System.getProperty("user.dir")).getName().equals("nifi_testharness_nifi_home")
+ * </tt></pre>
+ * </p>
+ *
+ * <p>
+ * Before {@code TestNiFiInstance} can be used, it has to be configured
via its builder
+ * interface:
+ * <ul>
+ * <li>
+ * {@link Builder#setFlowXmlToInstallForTesting(File)} specifies the
location of the NiFi binary
--- End diff --
I think this should refer to `setNiFiBinaryDistributionZip` instead
---
