Add ResourceUtils abstract utility class containing operations for working with Resource objects and byte arrays.

Resolves gh-92.

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

@@ -0,0 +1,159 @@
+/*
+ * 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.support;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+
+import org.junit.Test;
+
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.WritableResource;
+
+/**
+ * Unit Tests for {@link ResourceUtils}.
+ *
+ * @author John Blum
+ * @see org.junit.Test
+ * @see org.mockito.Mockito
+ * @see org.springframework.core.io.Resource
+ * @see org.springframework.core.io.WritableResource
+ * @see org.springframework.geode.core.io.support.ResourceUtils
+ * @since 1.3.1
+ */
+public class ResourceUtilsUnitTests {
+
+	@Test
+	public void getWritableResourceReturnsWritableResourceFromResource() {
+
+		WritableResource mockResource = mock(WritableResource.class);
+
+		doReturn(true).when(mockResource).isWritable();
+
+		assertThat(ResourceUtils.getWritableResource(mockResource)).isEqualTo(mockResource);
+
+		verify(mockResource, times(1)).isWritable();
+		verifyNoMoreInteractions(mockResource);
+	}
+
+	@Test(expected = IllegalStateException.class)
+	public void getWritableResourceFromResourceThrowsIllegalStateException() {
+
+		Resource mockResource = mock(Resource.class);
+
+		doReturn("MOCK").when(mockResource).getDescription();
+
+		try {
+			ResourceUtils.getWritableResource(mockResource);
+		}
+		catch (IllegalStateException expected) {
+
+			assertThat(expected).hasMessage("Resource [MOCK] is not writable");
+			assertThat(expected).hasNoCause();
+
+			throw expected;
+		}
+		finally {
+			verify(mockResource, times(1)).getDescription();
+			verifyNoMoreInteractions(mockResource);
+		}
+	}
+
+	@Test(expected = IllegalStateException.class)
+	public void getWritableResourceFromNullThrowsIllegalStateException() {
+
+		try {
+			ResourceUtils.getWritableResource(null);
+		}
+		catch (IllegalStateException expected) {
+
+			assertThat(expected).hasMessage("Resource [null] is not writable");
+			assertThat(expected).hasNoCause();
+
+			throw expected;
+		}
+	}
+
+	@Test(expected = IllegalStateException.class)
+	public void getWritableResourceFromNonWritableWritableResourceThrowsIllegalStateException() {
+
+		WritableResource mockResource = mock(WritableResource.class);
+
+		doReturn("TEST").when(mockResource).getDescription();
+		doReturn(false).when(mockResource).isWritable();
+
+		try {
+			ResourceUtils.getWritableResource(mockResource);
+		}
+		catch (IllegalStateException expected) {
+
+			assertThat(expected).hasMessage("Resource [TEST] is not writable");
+			assertThat(expected).hasNoCause();
+
+			throw expected;
+		}
+		finally {
+			verify(mockResource, times(1)).getDescription();
+			verify(mockResource, times(1)).isWritable();
+			verifyNoMoreInteractions(mockResource);
+		}
+	}
+
+	@Test
+	public void isNotEmptyWithNonEmptyByteArrayReturnsTrue() {
+
+		byte[] array = {
+			(byte) 0xCA,
+			(byte) 0xFE,
+			(byte) 0xBA,
+			(byte) 0xBE
+		};
+
+		assertThat(ResourceUtils.isNotEmpty(array)).isTrue();
+	}
+
+	@Test
+	public void isNotEmptyWithEmptyByteArrayReturnsFalse() {
+		assertThat(ResourceUtils.isNotEmpty(new byte[0])).isFalse();
+	}
+
+	@Test
+	public void isNotEmptyWithNullByteArrayReturnsFalse() {
+		assertThat(ResourceUtils.isNotEmpty(null)).isFalse();
+	}
+
+	@Test
+	public void nullSafeDescriptionWithNonNullResource() {
+
+		Resource mockResource = mock(Resource.class);
+
+		doReturn("TEST").when(mockResource).getDescription();
+
+		assertThat(ResourceUtils.nullSafeGetDescription(mockResource)).isEqualTo("TEST");
+
+		verify(mockResource, times(1)).getDescription();
+		verifyNoMoreInteractions(mockResource);
+	}
+
+	@Test
+	public void nullSafeGetDescriptionWithNullResource() {
+		assertThat(ResourceUtils.nullSafeGetDescription(null)).isEqualTo(null);
+	}
+}