tests: enable alertnotify test for Windows

The semantics of "echo" are different there and they change the resulting text,
but they're still correct and predictable.

src/test/alert_tests.cpp

@@ -154,9 +154,6 @@ BOOST_AUTO_TEST_CASE(AlertApplies)
 }
 
 
-// This uses sh 'echo' to test the -alertnotify function, writing to a
-// /tmp file. So skip it on Windows:
-#ifndef WIN32
 BOOST_AUTO_TEST_CASE(AlertNotify)
 {
     SetMockTime(11);
@@ -171,15 +168,24 @@ BOOST_AUTO_TEST_CASE(AlertNotify)
 
     std::vector<std::string> r = read_lines(temp);
     BOOST_CHECK_EQUAL(r.size(), 4u);
+
+// Windows built-in echo semantics are different than posixy shells. Quotes and
+// whitespace are printed literally.
+
+#ifndef WIN32
     BOOST_CHECK_EQUAL(r[0], "Alert 1");
     BOOST_CHECK_EQUAL(r[1], "Alert 2, cancels 1");
     BOOST_CHECK_EQUAL(r[2], "Alert 2, cancels 1");
     BOOST_CHECK_EQUAL(r[3], "Evil Alert; /bin/ls; echo "); // single-quotes should be removed
-
+#else
+    BOOST_CHECK_EQUAL(r[0], "'Alert 1' ");
+    BOOST_CHECK_EQUAL(r[1], "'Alert 2, cancels 1' ");
+    BOOST_CHECK_EQUAL(r[2], "'Alert 2, cancels 1' ");
+    BOOST_CHECK_EQUAL(r[3], "'Evil Alert; /bin/ls; echo ' ");
+#endif
     boost::filesystem::remove(temp);
 
     SetMockTime(0);
 }
-#endif
 
 BOOST_AUTO_TEST_SUITE_END()