Add unit test for X-11 license match

Added to see if the library is the cause of
spdx/spdx-online-tools#540

Signed-off-by: Gary O'Neall <gary@sourceauditor.com>

TestFiles/x-11-pthreads.txt

@@ -0,0 +1,21 @@
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the names of the authors or their
+institutions shall not be used in advertising or otherwise to promote the
+sale, use or other dealings in this Software without prior written
+authorization from the authors.

src/test/java/org/spdx/utility/compare/LicenseCompareHelperTest.java

@@ -101,6 +101,7 @@ public class LicenseCompareHelperTest extends TestCase {
     static final String GPL_2_NL = "TestFiles" + File.separator + "GPL-2.0-NL.txt";
     static final String GPL_2_TEMPLATE = "TestFiles" + File.separator + "GPL-2.0-only.template.txt";
     static final String IMAGE_MAGIK_TEMPLATE = "TestFiles" + File.separator + "ImageMagick.template.txt";
+    static final String X_11_PTHREADS = "TestFiles" + File.separator + "x-11-pthreads.txt";
 
 	IModelStore modelStore;
 	IModelCopyManager copyManager;
@@ -989,4 +990,12 @@ public void testAPIConsistency() throws InvalidSPDXAnalysisException, SpdxCompar
 			assertAPIConsistency("MPL-2.0",      UnitTestHelper.fileToText(MPL_2_FROM_MOZILLA_FILE));
 		}
 	}
+
+	public void testX11Pthreads() throws InvalidSPDXAnalysisException, SpdxCompareException, IOException {
+		String licText = UnitTestHelper.fileToText(X_11_PTHREADS);
+		String[] result = LicenseCompareHelper.matchingStandardLicenseIds(licText);
+		assertEquals(0, result.length);
+		ListedLicense license = ListedLicenses.getListedLicenses().getListedLicenseById("X11-distribute-modifications-variant");
+		assertTrue(LicenseCompareHelper.isTextStandardLicense(license, licText).isDifferenceFound());
+	}
 }