Improved tests for VersionInfoCommand

Author: pesse

src/test/java/org/utplsql/cli/VersionInfoCommandIT.java

@@ -1,23 +1,61 @@
 package org.utplsql.cli;
 
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.utplsql.cli.util.SystemOutCapturer;
+
+import java.io.IOException;
+import java.util.Arrays;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 public class VersionInfoCommandIT {
 
+    private SystemOutCapturer capturer;
+
+    @BeforeEach
+    public void setupCaptureSystemOut() {
+        capturer = new SystemOutCapturer();
+    }
+
+    private int getNonEmptyLines(String content) {
+        return (int) Arrays.stream(content.split("[\n|\r]"))
+                .filter(line -> !line.isEmpty())
+                .count();
+    }
+
+    private void assertNumberOfLines( int expected, String content ) {
+        int numOfLines = getNonEmptyLines(content);
+        assertEquals(expected, numOfLines, String.format("Expected output to have %n lines, but got %n", expected, numOfLines));
+    }
     @Test
     public void infoCommandRunsWithoutConnection() throws Exception {
 
+        capturer.start();
+
         int result = TestHelper.runApp("info");
 
+        String output = capturer.stop();
+
         assertEquals(0, result);
+        assertNumberOfLines(2, output);
     }
     @Test
     public void infoCommandRunsWithConnection() throws Exception {
 
+        capturer.start();
+
         int result = TestHelper.runApp("info", TestHelper.getConnectionString());
 
+        String output = capturer.stop();
+
         assertEquals(0, result);
+        assertNumberOfLines(3, output);
+    }
+
+    @AfterEach
+    public void cleanupCaptureSystemOut() throws IOException {
+        capturer.stop();
     }
 }

src/test/java/org/utplsql/cli/util/SystemOutCapturer.java

@@ -0,0 +1,74 @@
+package org.utplsql.cli.util;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.util.Arrays;
+import java.util.List;
+
+/** All credit to Manasjyoti Sharma: https://stackoverflow.com/a/30665299
+ */
+public class SystemOutCapturer {
+    private ByteArrayOutputStream baos;
+    private PrintStream previous;
+    private boolean capturing;
+
+    public void start() {
+        if (capturing) {
+            return;
+        }
+
+        capturing = true;
+        previous = System.out;
+        baos = new ByteArrayOutputStream();
+
+        OutputStream outputStreamCombiner =
+                new OutputStreamCombiner(Arrays.asList(previous, baos));
+        PrintStream custom = new PrintStream(outputStreamCombiner);
+
+        System.setOut(custom);
+    }
+
+    public String stop() {
+        if (!capturing) {
+            return "";
+        }
+
+        System.setOut(previous);
+
+        String capturedValue = baos.toString();
+
+        baos = null;
+        previous = null;
+        capturing = false;
+
+        return capturedValue;
+    }
+
+    private static class OutputStreamCombiner extends OutputStream {
+        private List<OutputStream> outputStreams;
+
+        public OutputStreamCombiner(List<OutputStream> outputStreams) {
+            this.outputStreams = outputStreams;
+        }
+
+        public void write(int b) throws IOException {
+            for (OutputStream os : outputStreams) {
+                os.write(b);
+            }
+        }
+
+        public void flush() throws IOException {
+            for (OutputStream os : outputStreams) {
+                os.flush();
+            }
+        }
+
+        public void close() throws IOException {
+            for (OutputStream os : outputStreams) {
+                os.close();
+            }
+        }
+    }
+}