diff --git a/learn.c b/learn.c
index 3356ba1..fd14b64 100644
--- a/learn.c
+++ b/learn.c
@@ -690,6 +690,7 @@ varnam_is_known_word(varnam* handle, const char* word)
         return 0;
 }
 
+/*Gets the stemrule for a particular ending from the database*/
 int
 varnam_get_stem(varnam* handle, const char* old_ending, const char *new_ending)
 {
@@ -730,6 +731,7 @@ varnam_get_stem(varnam* handle, const char* old_ending, const char *new_ending)
 }
 
 
+/*Stems the supplied word*/
 int
 varnam_stem(varnam *handle, char *word)
 {
@@ -738,6 +740,13 @@ varnam_stem(varnam *handle, char *word)
     char *ending,*new_ending;
     char *p;
 
+
+    if(word == NULL)
+    {
+        set_last_error(handle, "Cannot stem empty word");
+        return VARNAM_ERROR;
+    }
+
     word_buf = strbuf_init(strlen(word));
     strbuf_add(word_buf, word);
     new_ending = strbuf_init(15);
@@ -766,6 +775,4 @@ varnam_stem(varnam *handle, char *word)
 
     else
         return VARNAM_ERROR;
-
-    
 }
\ No newline at end of file
diff --git a/strbuf.c b/strbuf.c
index c5359b4..fdc6b3d 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -178,7 +178,30 @@ int strbuf_addvf(struct strbuf *string, const char *format, va_list args)
 }
 
 /*
-    Returns the last unicode character of the word
+ * Gets each unicode character in this string
+ * returned result should be destroyed
+ * */
+varray*
+strbuf_chars(strbuf *b)
+{
+  const unsigned char *ustring; const char *inputcopy;
+  int bytes_read;
+  varray *chars;
+  strbuf *tmp;
+
+  inputcopy = b->buffer;
+  chars = varray_init();
+  while (*inputcopy != '\0') {
+    READ_A_UTF8_CHAR (ustring, inputcopy, bytes_read);
+    tmp = strbuf_init(8);
+    strbuf_add_bytes (tmp, inputcopy - bytes_read, bytes_read);
+    varray_push (chars, strbuf_detach(tmp));
+    bytes_read = 0;
+  }
+  return chars;
+}
+
+ /*   Returns the last unicode character of the word
 */
 char*
 strbuf_get_ending(strbuf *word)
@@ -192,11 +215,6 @@ strbuf_get_ending(strbuf *word)
         return (char*)characters->memory[characters->index];
 }
 
-/*
-    decreases the index of the word by 
-    the length of its ending
-*/
-
 void strbuf_destroy(void *s)
 {
     strbuf *string;
diff --git a/symbol-table.c b/symbol-table.c
index 1afeece..5f039eb 100644
--- a/symbol-table.c
+++ b/symbol-table.c
@@ -324,6 +324,8 @@ vst_persist_token(
     return VARNAM_SUCCESS;
 }
 
+/*Stores a stem rule into the database*/
+
 int vst_persist_stemrule(varnam *handle, const char* old_ending, const char* new_ending, int level)
 {
     sqlite3 *db;
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index a1b0e04..a5dfac5 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -27,6 +27,7 @@ list (APPEND TEST_FILES
   export-words.c
   strbuftest.c
   varnamc_tests.c
+  stemmer_tests.c
   )
 
 set(test_executable_name runtests)
diff --git a/tests/stemmer_tests.c b/tests/stemmer_tests.c
new file mode 100644
index 0000000..b2ed366
--- /dev/null
+++ b/tests/stemmer_tests.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) Navaneeth.K.N
+ *
+ * This is part of libvarnam. See LICENSE.txt for the license
+ */
+
+#include <check.h>
+#include <stdio.h>
+#include <malloc.h>
+#include "testcases.h"
+#include "../varnam.h"
+
+void setup_test_data()
+{
+	int rc;
+	char **msg;
+	char *filename = get_unique_filename();
+
+	reinitialize_varnam_instance(filename);
+	ensure_schema_exists(varnam_instance, msg);
+}
+
+START_TEST (insert_stemrule)
+{
+	int rc;
+	char *empty_word="";
+
+	rc = varnam_create_stemrule(varnam_instance, empty_word, "ല", 1);
+	assert_error(rc);
+
+	rc = varnam_create_stemrule(varnam_instance, "ക", "ല", 0);
+	assert_error(rc);
+
+	rc = varnam_create_stemrule(varnam_instance, "ക", "ല", 4);
+	assert_error(rc);
+
+	rc = varnam_create_stemrule(varnam_instance, "ക", "ല", 1);
+	assert_success(rc);
+}
+END_TEST
+
+START_TEST (stem_word)
+{
+	int rc;
+	char *word;;
+	char *empty_word=NULL;
+
+	word = (char*)malloc(sizeof("പലക"));
+	strcpy(word, "പലക");
+	
+	rc = varnam_create_stemrule(varnam_instance, "ക", "ല", 1);
+	assert_success(rc);
+
+	rc = varnam_stem(varnam_instance, word);
+	assert_success(rc);
+	ck_assert_str_eq(word, "പലല");
+
+	rc = varnam_stem(varnam_instance, empty_word);
+	assert_error(rc);
+}
+END_TEST
+
+TCase* get_stemmer_tests()
+{
+ 	TCase* tcase = tcase_create("stemmer");
+ 	tcase_add_checked_fixture(tcase, setup, teardown);
+ 	tcase_add_checked_fixture(tcase, setup_test_data, NULL);
+ 	tcase_add_test(tcase, insert_stemrule);
+ 	tcase_add_test(tcase, stem_word);
+ 	return tcase;
+}
\ No newline at end of file
diff --git a/tests/test-runner.c b/tests/test-runner.c
index 6567e4a..4dd8f98 100644
--- a/tests/test-runner.c
+++ b/tests/test-runner.c
@@ -31,6 +31,7 @@ int main(int argc, char **argv)
     suite_add_tcase (suite, get_learning_tests());
     suite_add_tcase (suite, get_export_tests());
     suite_add_tcase (suite, get_token_creation_tests());
+    suite_add_tcase (suite, get_stemmer_tests());
 
     util = suite_create ("util");
     suite_add_tcase (util, get_strbuf_tests());
@@ -45,6 +46,7 @@ int main(int argc, char **argv)
     srunner_set_xml (runner, "testrun.xml");
     srunner_set_fork_status (runner, CK_NOFORK);
     srunner_run_all (runner, CK_NORMAL);
+    
     failed = srunner_ntests_failed (runner);
     srunner_free (runner);
 
diff --git a/varnam.c b/varnam.c
index 5540a8a..f23830c 100644
--- a/varnam.c
+++ b/varnam.c
@@ -675,6 +675,18 @@ int varnam_create_stemrule(varnam* handle, const char* old_ending, const char* n
 {
 	int rc;
 
+    if(old_ending == NULL || strlen(old_ending) == 0)
+    {
+        set_last_error(handle, "No ending supplied");
+        return VARNAM_ERROR;
+    }
+
+    if(level < 1 || level > 3)
+    {
+        set_last_error(handle, "Invalid level");
+        return VARNAM_ERROR;
+    }
+
     rc = vst_persist_stemrule(handle, old_ending, new_ending, level);
     
     if(rc != VARNAM_SUCCESS)