Update URL homograph rules.

test/unitTest/java/org/thoughtcrime/securesms/linkpreview/LinkPreviewUtilTest.java

@@ -8,17 +8,62 @@ import static junit.framework.TestCase.assertTrue;
 public class LinkPreviewUtilTest {
 
   @Test
-  public void isLegal_allLatin() {
-    assertTrue(LinkPreviewUtil.isLegalUrl("https://signal.org"));
+  public void isLegal_allAscii_noProtocol() {
+    assertTrue(LinkPreviewUtil.isLegalUrl("google.com"));
   }
 
   @Test
-  public void isLegal_latinAndCyrillic() {
-    assertFalse(LinkPreviewUtil.isLegalUrl("https://www.аmazon.com"));
+  public void isLegal_allAscii_noProtocol_subdomain() {
+    assertTrue(LinkPreviewUtil.isLegalUrl("foo.google.com"));
   }
 
   @Test
-  public void isLegal_latinAndGreek() {
-    assertFalse(LinkPreviewUtil.isLegalUrl("https://www.αpple.com"));
+  public void isLegal_allAscii_subdomain() {
+    assertTrue(LinkPreviewUtil.isLegalUrl("https://foo.google.com"));
+  }
+
+  @Test
+  public void isLegal_allAscii_subdomain_path() {
+    assertTrue(LinkPreviewUtil.isLegalUrl("https://foo.google.com/some/path.html"));
+  }
+
+  @Test
+  public void isLegal_cyrillicHostAsciiTld() {
+    assertFalse(LinkPreviewUtil.isLegalUrl("http://кц.com"));
+  }
+
+  @Test
+  public void isLegal_cyrillicHostAsciiTld_noProtocol() {
+    assertFalse(LinkPreviewUtil.isLegalUrl("кц.com"));
+  }
+
+  @Test
+  public void isLegal_mixedHost_noProtocol() {
+    assertFalse(LinkPreviewUtil.isLegalUrl("http://asĸ.com"));
+  }
+
+  @Test
+  public void isLegal_cyrillicHostAndTld_noProtocol() {
+    assertTrue(LinkPreviewUtil.isLegalUrl("кц.рф"));
+  }
+
+  @Test
+  public void isLegal_cyrillicHostAndTld_asciiPath_noProtocol() {
+    assertTrue(LinkPreviewUtil.isLegalUrl("кц.рф/some/path"));
+  }
+
+  @Test
+  public void isLegal_cyrillicHostAndTld_asciiPath() {
+    assertTrue(LinkPreviewUtil.isLegalUrl("https://кц.рф/some/path"));
+  }
+
+  @Test
+  public void isLegal_asciiSubdomain_cyrillicHostAndTld() {
+    assertFalse(LinkPreviewUtil.isLegalUrl("http://foo.кц.рф"));
+  }
+
+  @Test
+  public void isLegal_emptyUrl() {
+    assertFalse(LinkPreviewUtil.isLegalUrl(""));
   }
 }