[tests] Add test on input contract

Signed-off-by: Emmanuel Bigeon <emmanuel@bigeon.fr>

gclc-test/src/test/java/net/bigeon/gclc/test/InputContractTest.java

@@ -0,0 +1,52 @@
+/** gclc-test: InputContractTest
+ * Created on Apr. 6, 2020
+ */
+package net.bigeon.gclc.test;
+
+import static org.junit.Assert.fail;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.PipedInputStream;
+import java.io.PipedOutputStream;
+import java.io.PrintStream;
+import java.nio.charset.StandardCharsets;
+
+import org.junit.After;
+import org.junit.Test;
+
+import net.bigeon.gclc.manager.EmptyInput;
+import net.bigeon.gclc.manager.StreamConsoleInput;
+
+/** @author Emmanuel Bigeon */
+public class InputContractTest {
+
+    /** Test method for
+     * {@link net.bigeon.gclc.test.InputContract#testInputContract(java.util.function.Supplier)}. */
+    @Test
+    public void testTestInputContract() throws IOException, InterruptedException {
+        final InputContract contract = new InputContract();
+        try (InputStream in = new PipedInputStream(new PipedOutputStream());
+                PrintStream out = new PrintStream("temp.txt")) {
+            contract.testInputContract(
+                    () -> new StreamConsoleInput(out, in, StandardCharsets.UTF_8));
+        }
+
+        try {
+            contract.testInputContract(() -> EmptyInput.INSTANCE);
+            fail("Empty input does not fit the contract for inputs since it cannot be closed.");
+        } catch (final AssertionError e) {
+            // ok
+        }
+    }
+
+    @After
+    public void tearDown() {
+        final File f = new File("temp.txt");
+        if (f.exists()) {
+            f.delete();
+        }
+    }
+
+}