add unit tests for IOFunctions#bracket

jbgi · jbgi · commit 3107a2f11f59 · 2016-05-24T07:41:22.000+02:00
diff --git a/core/src/test/java/fj/data/IOFunctionsTest.java b/core/src/test/java/fj/data/IOFunctionsTest.java
@@ -0,0 +1,64 @@
+package fj.data;
+
+import fj.Unit;
+import org.hamcrest.core.Is;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.*;
+import java.io.Reader;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.junit.Assert.*;
+
+public class IOFunctionsTest {
+
+  @Test
+  public void bracket_happy_path() throws Exception {
+    AtomicBoolean closed = new AtomicBoolean();
+    Reader reader = new StringReader("Read OK") {
+      @Override
+      public void close() {
+        super.close();
+        closed.set(true);
+      }
+    };
+
+    IO<String> bracketed = IOFunctions.bracket(
+        () -> reader,
+        IOFunctions.closeReader,
+        r -> () -> new BufferedReader(r).readLine()
+    );
+
+    Assert.assertThat(bracketed.run(), Is.is("Read OK"));
+    Assert.assertThat(closed.get(), Is.is(true));
+  }
+
+  @Test
+  public void bracket_exception_path() throws Exception {
+    AtomicBoolean closed = new AtomicBoolean();
+    Reader reader = new StringReader("Read OK") {
+      @Override
+      public void close() {
+        super.close();
+        closed.set(true);
+        throw new IllegalStateException("Should be suppressed");
+      }
+    };
+
+    IO<String> bracketed = IOFunctions.bracket(
+        () -> reader,
+        IOFunctions.closeReader,
+        r -> () -> {throw new IllegalArgumentException("OoO");}
+    );
+
+    try {
+      bracketed.run();
+      fail("Exception expected");
+    } catch (IllegalArgumentException e) {
+      Assert.assertThat(e.getMessage(), Is.is("OoO"));
+    }
+    Assert.assertThat(closed.get(), Is.is(true));
+  }
+
+}
