Escape addresses in thread, recipient pref, and group databases

Fixes #6847
// FREEBIE

test/unitTest/java/org/thoughtcrime/securesms/util/DelimiterUtilTest.java

@@ -0,0 +1,56 @@
+package org.thoughtcrime.securesms.util;
+
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static junit.framework.Assert.assertEquals;
+
+public class DelimiterUtilTest {
+
+  @Before
+  public void setup() {}
+
+  @Test
+  public void testEscape() {
+    assertEquals(DelimiterUtil.escape("MTV Music", ' '), "MTV\\ Music");
+    assertEquals(DelimiterUtil.escape("MTV  Music", ' '), "MTV\\ \\ Music");
+
+    assertEquals(DelimiterUtil.escape("MTV,Music", ','), "MTV\\,Music");
+    assertEquals(DelimiterUtil.escape("MTV,,Music", ','), "MTV\\,\\,Music");
+
+    assertEquals(DelimiterUtil.escape("MTV Music", '+'), "MTV Music");
+  }
+
+  @Test
+  public void testSplit() {
+    String[] parts = DelimiterUtil.split("MTV\\ Music", ' ');
+    assertEquals(parts.length, 1);
+    assertEquals(parts[0], "MTV\\ Music");
+
+    parts = DelimiterUtil.split("MTV Music", ' ');
+    assertEquals(parts.length, 2);
+    assertEquals(parts[0], "MTV");
+    assertEquals(parts[1], "Music");
+  }
+
+  @Test
+  public void testEscapeSplit() {
+    String   input        = "MTV Music";
+    String   intermediate = DelimiterUtil.escape(input, ' ');
+    String[] parts        = DelimiterUtil.split(intermediate, ' ');
+
+    assertEquals(parts.length, 1);
+    assertEquals(parts[0], "MTV\\ Music");
+    assertEquals(DelimiterUtil.unescape(parts[0], ' '), "MTV Music");
+
+    input        = "MTV\\ Music";
+    intermediate = DelimiterUtil.escape(input, ' ');
+    parts        = DelimiterUtil.split(intermediate, ' ');
+
+    assertEquals(parts.length, 1);
+    assertEquals(parts[0], "MTV\\\\ Music");
+    assertEquals(DelimiterUtil.unescape(parts[0], ' '), "MTV\\ Music");
+  }
+
+}