Adding tests for GlobMatch

Signed-off-by: Niyati Aggarwal <[email protected]>

libs/common/src/main/java/org/opensearch/common/Glob.java

@@ -49,6 +49,9 @@ public class Glob {
      * @return whether the String matches the given pattern
      */
     public static boolean globMatch(String pattern, String str) {
+        if (pattern == null || str == null) {
+            return false;
+        }
         int sIdx = 0, pIdx = 0, match = 0, wildcardIdx = -1;
         while (sIdx < str.length()) {
             // both chars matching, incrementing both pointers

server/src/test/java/org/opensearch/common/GlobTests.java

@@ -0,0 +1,67 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.common;
+
+import org.opensearch.test.OpenSearchTestCase;
+
+public class GlobTests extends OpenSearchTestCase {
+
+    public void testGlobMatchForNull() {
+        assertFalse(Glob.globMatch(null, "test"));
+        assertFalse(Glob.globMatch("test", null));
+        assertFalse(Glob.globMatch(null, null));
+    }
+
+    public void testGlobMatchNoWildcard() {
+        assertTrue(Glob.globMatch("abcd", "abcd"));
+        assertFalse(Glob.globMatch("abcd", "foobar"));
+    }
+
+    public void testGlobMatchSingleWildcard() {
+        assertTrue(Glob.globMatch("*foo", "barfoo"));
+        assertFalse(Glob.globMatch("*foo", "foobar"));
+        assertTrue(Glob.globMatch("foo*", "foobarfoo"));
+        assertFalse(Glob.globMatch("foo*", "barfoobar"));
+        assertTrue(Glob.globMatch("foo*bar", "foobarnfoosbar"));
+    }
+
+    public void testGlobMatchMultipleWildcards() {
+        assertTrue(Glob.globMatch("*foo*", "barfoobar"));
+        assertFalse(Glob.globMatch("*foo*", "baroofbar"));
+        assertTrue(Glob.globMatch("*foo*bar", "abcdfooefghbar"));
+        assertFalse(Glob.globMatch("*foo*bar", "foonotbars"));
+    }
+
+    public void testGlobalMatchDoubleWildcard() {
+        assertTrue(Glob.globMatch("**foo", "barbarfoo"));
+        assertFalse(Glob.globMatch("**foo", "barbarfoowoof"));
+        assertTrue(Glob.globMatch("**bar**", "foobarfoo"));
+        assertFalse(Glob.globMatch("**bar**", "foobanfoo"));
+    }
+
+    public void testGlobMatchMultipleCharactersWithSingleWildcard() {
+        assertTrue(Glob.globMatch("a*b", "acb"));
+        assertTrue(Glob.globMatch("f*oo", "foo"));
+        assertTrue(Glob.globMatch("a*b", "aab"));
+        assertTrue(Glob.globMatch("a*b", "aaab"));
+    }
+
+    public void testGlobMatchWildcardWithEmptyString() {
+        assertTrue(Glob.globMatch("*", ""));
+        assertTrue(Glob.globMatch("a*", "a"));
+        assertFalse(Glob.globMatch("a*", ""));
+    }
+
+    public void testGlobMatchMultipleWildcardsWithMultipleCharacters() {
+        assertTrue(Glob.globMatch("a*b*c", "abc"));
+        assertTrue(Glob.globMatch("a*b*c", "axxxbxbc"));
+        assertFalse(Glob.globMatch("a*b*c", "abca"));
+        assertFalse(Glob.globMatch("a*b*c", "ac"));
+    }
+}