Add unit tests

core-java-modules/core-java-console/src/test/java/com/baeldung/systemin/SystemInReadUnitTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.systemin;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+import org.junit.jupiter.api.Test;
+
+public class SystemInReadUnitTest {
+    @Test
+    void givenUserInput_whenUsingReadMultipleCharacters_thenRead() {
+        System.setIn(new ByteArrayInputStream("Hello\n".getBytes()));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outputStream));
+        SystemInRead.readMultipleCharacters();
+
+        assertEquals("Enter characters (Press 'Enter' to quit):\n" + "Hello", outputStream.toString().trim());
+    }
+
+    @Test
+    void givenUserInput_whenUsingReadSingleCharacter_thenRead() {
+        System.setIn(new ByteArrayInputStream("A".getBytes()));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outputStream));
+        SystemInRead.readSingleCharacter();
+
+        assertEquals("Enter a character:\nA", outputStream.toString().trim());
+    }
+
+    @Test
+    void givenUserInput_whenUsingReadSingleCharacter_thenReading() {
+        System.setIn(new ByteArrayInputStream("ABC".getBytes()));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(outputStream));
+        SystemInRead.readWithParameters();
+
+        assertEquals("Data read: ABC\n" + "Bytes Read: 3", outputStream.toString().trim());
+    }
+}