docs: example input stream exception

Author: fugerit79

turbo-unit-core/src/main/java/org/fugerit/java/turbo/unit/core/ex/ExampleRuntimeException.java

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+package org.fugerit.java.turbo.unit.core.ex;
+
+public class ExampleRuntimeException extends RuntimeException {
+
+    public ExampleRuntimeException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+}

turbo-unit-core/src/main/java/org/fugerit/java/turbo/unit/core/io/ExampleReadStream.java

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+package org.fugerit.java.turbo.unit.core.io;
+
+import org.fugerit.java.turbo.unit.core.ex.ExampleRuntimeException;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * This is a simple class reading the content of an InputStream.
+ *
+ * If successful, a byte[] array containing the data read is returned.
+ *
+ * If an exception occurs, it is caught and rethrow as a RuntimeException.
+ *
+ */
+public class ExampleReadStream {
+
+    public byte[] readBytes( InputStream inputStream ) {
+        try ( ByteArrayOutputStream buffer = new ByteArrayOutputStream() ) {
+            byte[] data = new byte[1024];
+            int read = inputStream.read( data );
+            while ( read > 0 ) {
+                buffer.write( data, 0, read );
+                read = inputStream.read( data );
+            }
+            return buffer.toByteArray();
+        } catch ( IOException e ) {
+            String message = String.format( "Error reading input stream : %s", e );
+            throw new ExampleRuntimeException( message, e );
+        }
+    }
+
+}

turbo-unit-core/src/test/java/org/fugerit/java/turbo/unit/core/io/TestExampleReadStream.java

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+package org.fugerit.java.turbo.unit.core.io;
+
+import org.fugerit.java.turbo.unit.core.ex.ExampleRuntimeException;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * When testing {@link ExampleReadStream} it is easy to check the successful scenario.
+ *
+ * But if you want to try the Exception case too, some workaround it is needed.
+ *
+ * In this example, we are using a custom InputStream to generate an exception.
+ *
+ * I used something similar in the repository :
+ *
+ * https://github.com/fugerit-org/fj-lib/blob/main/fj-core/src/test/java/test/org/fugerit/java/core/testhelpers/FailInputStream.java
+ * https://github.com/fugerit-org/fj-lib/blob/main/fj-core/src/test/java/test/org/fugerit/java/core/cfg/store/TestConfigStore.java#L81
+ *
+ */
+class TestExampleReadStream {
+
+    @Test
+    void testKo() throws IOException {
+        ExampleReadStream example = new ExampleReadStream();
+        try (InputStream is = new InputStream() {
+            @Override
+            public int read() throws IOException {
+                if (Boolean.TRUE) {
+                    throw new IOException("read failed (by scenario)");
+                }
+                return 0;
+            }
+        }) {
+            Assertions.assertThrows(ExampleRuntimeException.class, () -> example.readBytes(is));
+        }
+    }
+
+    @Test
+    void testOk() throws IOException {
+        ExampleReadStream example = new ExampleReadStream();
+        String testOk = "OK";
+        try (InputStream is = new ByteArrayInputStream(testOk.getBytes())) {
+            // Assertions.assertThrows(ExampleRuntimeException.class, () -> example.readBytes(is));
+            byte[] data = example.readBytes(is);
+            Assertions.assertArrayEquals( data, testOk.getBytes() );
+        }
+    }
+
+}