isSingleToken return false for null and empty strings

Author: goneall

src/main/java/org/spdx/utility/compare/LicenseCompareHelper.java

@@ -238,8 +238,8 @@ public static String locateOriginalText(String fullLicenseText, int startToken,
 	 *         {@code false} otherwise.
 	 */
 	public static boolean isSingleTokenString(@Nullable String text) {
-		if (text == null || text.isEmpty()) {
-			return true; // Zero tokens is considered a single token string
+		if (text == null || text.trim().isEmpty()) {
+			return false;
 		}
 		Matcher m = LicenseTextHelper.TOKEN_SPLIT_PATTERN.matcher(text);
 		boolean found = false;

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

@@ -542,10 +542,10 @@ public void testLicenseEqualsNoneLicense() throws InvalidSPDXAnalysisException,
 	}
 
 	public void testisSingleTokenString() {
-		assertTrue(LicenseCompareHelper.isSingleTokenString(null));
-		assertTrue(LicenseCompareHelper.isSingleTokenString(""));
-		assertTrue(LicenseCompareHelper.isSingleTokenString(" "));
-		assertTrue(LicenseCompareHelper.isSingleTokenString("\n"));
+		assertFalse(LicenseCompareHelper.isSingleTokenString(null));
+		assertFalse(LicenseCompareHelper.isSingleTokenString(""));
+		assertFalse(LicenseCompareHelper.isSingleTokenString(" "));
+		assertFalse(LicenseCompareHelper.isSingleTokenString("\n"));
 		assertTrue(LicenseCompareHelper.isSingleTokenString("'"));
 		assertTrue(LicenseCompareHelper.isSingleTokenString(" '"));
 		assertTrue(LicenseCompareHelper.isSingleTokenString("' "));