Add example i/o test

10_Blackjack/java/test/GameTest.java

@@ -0,0 +1,40 @@
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.EOFException;
+import java.io.Reader;
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.io.UncheckedIOException;
+
+public class GameTest {
+
+    private StringReader in;
+    private StringWriter out;
+    private Game game;
+
+    private void givenInput(String input) {
+        Reader in = new StringReader("\u2404"); // U+2404 is "End of Transmission" sent by CTRL+D (or CTRL+Z on Windows)
+        StringWriter out = new StringWriter();
+        UserIo userIo = new UserIo(in, out);
+        Deck deck = new Deck((cards) -> cards);
+        game = new Game(deck, userIo);
+    }
+
+    @Test
+    public void shouldQuitOnCtrlD() {
+        // Given
+        givenInput("\u2404"); // U+2404 is "End of Transmission" sent by CTRL+D (or CTRL+Z on Windows)
+
+        // When
+        Exception e = assertThrows(UncheckedIOException.class, game::run);
+
+        // Then
+        assertTrue(e.getCause() instanceof EOFException);
+        assertEquals("!END OF INPUT", e.getMessage());
+    }
+}