Add AbstractResourceReader base class defining operations common to all ResourceReaders.

Resolves gh-92.

spring-geode/src/test/java/org/springframework/geode/core/io/AbstractResourceReaderUnitTests.java

@@ -0,0 +1,153 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * 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
+ *
+ *     https://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.springframework.geode.core.io;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doCallRealMethod;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.junit.Test;
+
+import org.springframework.core.io.Resource;
+import org.springframework.dao.DataAccessResourceFailureException;
+
+/**
+ * Unit Tests for {@link AbstractResourceReader}.
+ *
+ * @author John Blum
+ * @see org.junit.Test
+ * @see org.mockito.Mockito
+ * @see org.springframework.core.io.Resource
+ * @see org.springframework.geode.core.io.AbstractResourceReader
+ * @since 1.3.1
+ */
+public class AbstractResourceReaderUnitTests {
+
+	@Test
+	public void readCallsDoRead() throws IOException {
+
+		byte[] array = { (byte) 0xCA, (byte) 0xFE, (byte) 0xBA, (byte) 0xBE };
+
+		AbstractResourceReader mockResourceReader = mock(AbstractResourceReader.class);
+
+		InputStream mockInputStream = mock((InputStream.class));
+
+		Resource mockResource = mock(Resource.class);
+
+		doCallRealMethod().when(mockResourceReader).read(any());
+		doReturn(true).when(mockResourceReader).isAbleToHandle(eq(mockResource));
+		doReturn(array).when(mockResourceReader).doRead(eq(mockInputStream));
+		doReturn(mockInputStream).when(mockResource).getInputStream();
+
+		assertThat(mockResourceReader.read(mockResource)).isEqualTo(array);
+
+		verify(mockResourceReader, times(1)).isAbleToHandle(eq(mockResource));
+		verify(mockResourceReader, times(1)).doRead(eq(mockInputStream));
+		verify(mockInputStream, times(1)).close();
+		verify(mockResource, times(1)).getInputStream();
+		verifyNoMoreInteractions(mockInputStream, mockResource);
+	}
+
+	@Test(expected = UnhandledResourceException.class)
+	public void readFromNullResourceThrowsUnhandledResourceException() {
+
+		AbstractResourceReader mockResourceReader = mock(AbstractResourceReader.class);
+
+		doCallRealMethod().when(mockResourceReader).read(any());
+
+		try {
+			mockResourceReader.read(null);
+		}
+		catch (UnhandledResourceException expected) {
+
+			assertThat(expected).hasMessage("Unable to handle Resource [null]");
+			assertThat(expected).hasNoCause();
+
+			throw expected;
+		}
+	}
+
+	@Test(expected = DataAccessResourceFailureException.class)
+	public void readThrowsDataAccessResourceFailureExceptionOnIoException() throws IOException {
+
+		AbstractResourceReader mockResourceReader = mock(AbstractResourceReader.class);
+
+		InputStream mockInputStream = mock((InputStream.class));
+
+		Resource mockResource = mock(Resource.class);
+
+		doCallRealMethod().when(mockResourceReader).read(any());
+		doReturn(true).when(mockResourceReader).isAbleToHandle(eq(mockResource));
+		doThrow(new IOException("TEST")).when(mockResourceReader).doRead(eq(mockInputStream));
+		doReturn("MOCK").when(mockResource).getDescription();
+		doReturn(mockInputStream).when(mockResource).getInputStream();
+
+		try {
+			mockResourceReader.read(mockResource);
+		}
+		catch (DataAccessResourceFailureException expected) {
+
+			assertThat(expected).hasMessageStartingWith("Failed to read from Resource [MOCK]");
+			assertThat(expected).hasCauseInstanceOf(IOException.class);
+			assertThat(expected.getCause()).hasMessage("TEST");
+			assertThat(expected.getCause()).hasNoCause();
+
+			throw expected;
+		}
+		finally {
+			verify(mockResourceReader, times(1)).doRead(eq(mockInputStream));
+			verify(mockInputStream, times(1)).close();
+			verify(mockResource, times(1)).getDescription();
+			verify(mockResource, times(1)).getInputStream();
+			verifyNoMoreInteractions(mockInputStream, mockResource);
+		}
+	}
+
+	@Test
+	public void isAbleToHandleNonNullResourceReturnsTrue() {
+
+		Resource mockResource = mock(Resource.class);
+
+		AbstractResourceReader mockResourceReader = mock(AbstractResourceReader.class);
+
+		doCallRealMethod().when(mockResourceReader).isAbleToHandle(any());
+
+		assertThat(mockResourceReader.isAbleToHandle(mockResource)).isTrue();
+
+		verifyNoInteractions(mockResource);
+	}
+
+	@Test
+	public void isAbleToHandleNullResourceReturnsFalse() {
+
+		AbstractResourceReader mockResourceReader = mock(AbstractResourceReader.class);
+
+		doCallRealMethod().when(mockResourceReader).isAbleToHandle(any());
+
+		assertThat(mockResourceReader.isAbleToHandle(null)).isFalse();
+	}
+}