From d23233d53b50e4aa93cd2095ec7227a14bdffd02 Mon Sep 17 00:00:00 2001
From: Klaus Reimer <k@ailis.de>
Date: Tue, 16 Apr 2013 19:13:16 +0200
Subject: [PATCH] Run USB unit tests also when lsusb command line tool can be
 executed and returns at least two devices

---
 .../java/de/ailis/usb4java/UsbAssume.java     | 47 ++++++++++++++++++-
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/src/test/java/de/ailis/usb4java/UsbAssume.java b/src/test/java/de/ailis/usb4java/UsbAssume.java
index 8f8ee8f..f54fc59 100644
--- a/src/test/java/de/ailis/usb4java/UsbAssume.java
+++ b/src/test/java/de/ailis/usb4java/UsbAssume.java
@@ -7,6 +7,10 @@ package de.ailis.usb4java;
 
 import static org.junit.Assume.assumeTrue;
 
+import java.io.BufferedReader;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+
 /**
  * USB-related assumptions.
  * 
@@ -14,14 +18,53 @@ import static org.junit.Assume.assumeTrue;
  */
 public class UsbAssume
 {
+    /** If USB tests are to be executed. */
+    private static Boolean usbTests;
+    
     /**
      * Assume that USB tests are enabled. Call this in the first line of
      * tests method or preparation methods when you want to ignore the
-     * tests when the property USB_TESTS is not set.
+     * tests when the system is not able to run the tests anyway.
+     * 
+     * USB tests can be controlled with the system property USB_TESTS. When
+     * set to true then USB tests are always run, if set to false then they
+     * are never run. If this property is not set then the command-line tool
+     * lsusb is called. If this tool returned at least two lines of text then
+     * USB tests are enabled. In all other cases they are disabled.
      */
     public static void assumeUsbTestsEnabled()
     {
+        if (usbTests == null && System.getProperty("USB_TESTS") != null)
+            usbTests = Boolean.valueOf(System.getProperty("USB_TESTS"));
+        if (usbTests == null)
+        {
+            usbTests = false;
+            try
+            {
+                final Process proc = Runtime.getRuntime().exec("lsusb");
+                if (proc.waitFor() == 0)
+                {
+                    InputStream inputStream = proc.getInputStream();
+                    try
+                    {
+                        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
+                        int lines = 0;
+                        while (reader.readLine() != null) lines++;
+                        usbTests = lines >= 2;
+                    }
+                    finally
+                    {
+                        inputStream.close();
+                    }
+                }
+            }
+            catch (Exception e)
+            {
+                // Ignored. USB tests are silently disabled when lsusb could
+                // not be run.
+            }
+        }
         assumeTrue("This test is ignored when USB_TESTS property is not set",
-            System.getProperty("USB_TESTS") != null);
+             usbTests);
     }
 }