cadonna commented on a change in pull request #9717:
URL: https://github.com/apache/kafka/pull/9717#discussion_r545110552
##########
File path:
streams/src/main/java/org/apache/kafka/streams/state/internals/RocksDBRangeIterator.java
##########
@@ -55,20 +56,36 @@
}
}
+ public byte[] getRawLastKey() {
+ return rawLastKey;
+ }
+
+ public boolean isForward() {
+ return forward;
+ }
+
+ public KeyValue<Bytes, byte[]> getNext() {
+ return super.makeNext();
+ }
+
+ public Comparator<byte[]> getComparator() {
+ return comparator;
+ }
+
@Override
public KeyValue<Bytes, byte[]> makeNext() {
- final KeyValue<Bytes, byte[]> next = super.makeNext();
+ final KeyValue<Bytes, byte[]> next = getNext();
if (next == null) {
return allDone();
} else {
- if (forward) {
- if (comparator.compare(next.key.get(), rawLastKey) <= 0) {
+ if (isForward()) {
+ if (getComparator().compare(next.key.get(), getRawLastKey())
<= 0) {
return next;
} else {
return allDone();
}
} else {
- if (comparator.compare(next.key.get(), rawLastKey) >= 0) {
+ if (getComparator().compare(next.key.get(), getRawLastKey())
>= 0) {
Review comment:
It is not a good idea to change a class due to unit tests if it is not
absolutely necessary. In this case it is definitely not necessary. See my
suggestion how to change the tests.
##########
File path:
streams/src/test/java/org/apache/kafka/streams/state/internals/RocksDBRangeIteratorTest.java
##########
@@ -0,0 +1,295 @@
+/*
+ * 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.kafka.streams.state.internals;
+
+import org.apache.kafka.common.utils.Bytes;
+import org.apache.kafka.streams.KeyValue;
+import org.junit.Test;
+
+import static org.easymock.EasyMock.expect;
+import static org.easymock.EasyMock.partialMockBuilder;
+import static org.easymock.EasyMock.replay;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.nullValue;
+import static org.hamcrest.core.Is.is;
+
+public class RocksDBRangeIteratorTest {
+
+ private RocksDBRangeIterator mockRocksDBRangeIterator() {
+ return partialMockBuilder(RocksDBRangeIterator.class)
+ .addMockedMethod("getNext")
+ .addMockedMethod("getRawLastKey")
+ .addMockedMethod("isForward")
+ .addMockedMethod("getComparator")
+ .createMock();
+ }
+
+ @Test
+ public void shouldReturnAllKeysInTheRangeInForwardDirection() {
+ final RocksDBRangeIterator rocksDBRangeIterator =
mockRocksDBRangeIterator();
+
+ final String key1 = "a";
+ final String key2 = "b";
+ final String key3 = "c";
+ final String key4 = "d";
+ final String value = "value";
+
+ final Bytes key1Bytes = Bytes.wrap(key1.getBytes());
+ final Bytes key2Bytes = Bytes.wrap(key2.getBytes());
+ final Bytes key3Bytes = Bytes.wrap(key3.getBytes());
+ final Bytes key4Bytes = Bytes.wrap(key4.getBytes());
+ final byte[] valueBytes = value.getBytes();
+
+ expect(rocksDBRangeIterator.getNext())
+ .andReturn(KeyValue.pair(key1Bytes, valueBytes))
+ .andReturn(KeyValue.pair(key2Bytes, valueBytes))
+ .andReturn(KeyValue.pair(key3Bytes, valueBytes))
+ .andReturn(KeyValue.pair(key4Bytes, valueBytes));
+
+ expect(rocksDBRangeIterator.getRawLastKey())
+ .andReturn(key3Bytes.get())
+ .anyTimes();
+
+ expect(rocksDBRangeIterator.isForward())
+ .andReturn(true)
+ .anyTimes();
+
+ expect(rocksDBRangeIterator.getComparator())
+ .andReturn(Bytes.BYTES_LEXICO_COMPARATOR)
+ .anyTimes();
+
+
+ replay(rocksDBRangeIterator);
+ assertThat(rocksDBRangeIterator.makeNext().key, is(key1Bytes));
+ assertThat(rocksDBRangeIterator.makeNext().key, is(key2Bytes));
+ assertThat(rocksDBRangeIterator.makeNext().key, is(key3Bytes));
+ assertThat(rocksDBRangeIterator.makeNext(), is(nullValue()));
Review comment:
You usually do not want to mock the class under test, because you want
to test it. Also partial mocks should only be used if absolutely necessary. A
rule of thumb is if a partial mock is needed then most probably the design has
a flaw.
In this specific case, you should mock RocksDB's iterator. For the class
under test, you should test `hasNext()`, `next()`, `peekNextKey()` and
`close()`, because those are the one exposed (`makeNext()` should actually de
declared as `protected`, IMO).
```suggestion
final String key1 = "a";
final String key2 = "b";
final String key3 = "c";
final String key4 = "d";
final String value = "value";
final Bytes key1Bytes = Bytes.wrap(key1.getBytes());
final Bytes key2Bytes = Bytes.wrap(key2.getBytes());
final Bytes key3Bytes = Bytes.wrap(key3.getBytes());
final Bytes key4Bytes = Bytes.wrap(key4.getBytes());
final byte[] valueBytes = value.getBytes();
final RocksIterator rocksIterator = mock(RocksIterator.class);
rocksIterator.seek(key1Bytes.get());
expect(rocksIterator.isValid())
.andReturn(true)
.andReturn(true)
.andReturn(true)
.andReturn(true)
.andReturn(false);
expect(rocksIterator.key())
.andReturn(key1Bytes.get())
.andReturn(key2Bytes.get())
.andReturn(key3Bytes.get())
.andReturn(key4Bytes.get());
expect(rocksIterator.value()).andReturn(valueBytes).times(4);
rocksIterator.next();
expectLastCall().times(4);
replay(rocksIterator);
final RocksDBRangeIterator rocksDBRangeIterator = new
RocksDBRangeIterator(
STORE_NAME,
rocksIterator,
Collections.emptySet(),
key1Bytes,
key4Bytes,
true
);
assertThat(rocksDBRangeIterator.hasNext(), is(true));
assertThat(rocksDBRangeIterator.next().key, is(key1Bytes));
assertThat(rocksDBRangeIterator.hasNext(), is(true));
assertThat(rocksDBRangeIterator.next().key, is(key2Bytes));
assertThat(rocksDBRangeIterator.hasNext(), is(true));
assertThat(rocksDBRangeIterator.next().key, is(key3Bytes));
assertThat(rocksDBRangeIterator.hasNext(), is(true));
assertThat(rocksDBRangeIterator.next().key, is(key4Bytes));
assertThat(rocksDBRangeIterator.hasNext(), is(false));
verify(rocksIterator);
```
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