diff --git a/assembly/test_decoder.ts b/assembly/test_decoder.ts
index 5317922..78d46f5 100644
--- a/assembly/test_decoder.ts
+++ b/assembly/test_decoder.ts
@@ -40,10 +40,8 @@ export function decode(data: string): Value {
   return res;
 }
 
-export function decodeRainCBOR_test(): bool {
+export function decodeRainCBOR_test(rainSequenceEncoded: string): bool {
   // Use: https://cbor.me/
-  const rainSequenceEncoded =
-    "A3004411223344011BFFC21BBF86CC199B02706170706C69636174696F6E2F63626F72A3004412345678011BFFE5FFB4A3FF2CDE02706170706C69636174696F6E2F6A736F6E";
   const buff = stringToArrayBuffer(rainSequenceEncoded);
   const decoder = new CBORDecoder(buff);
   const res = decoder.parse();
@@ -465,3 +463,11 @@ export function decodeAllInArray(): boolean {
     bytesResult
   );
 }
+
+export function decodeRandomString(dataStr:string): string {
+  const buff = stringToArrayBuffer(dataStr);
+
+  const decoder = new CBORDecoder(buff);
+  const res = decoder.parse();
+  return res.toString();
+}
diff --git a/assembly/test_encoder.ts b/assembly/test_encoder.ts
index eefca67..88aabf9 100644
--- a/assembly/test_encoder.ts
+++ b/assembly/test_encoder.ts
@@ -1,6 +1,6 @@
 import { CBOREncoder } from "./encoder";
 
-export function encodeRainDocument(): ArrayBuffer {
+export function encodeRainDocument(dataStr:string): ArrayBuffer {
   const encoder = new CBOREncoder();
   encoder.addObject(3);
 
@@ -9,10 +9,9 @@ export function encodeRainDocument(): ArrayBuffer {
 
   //  h'11223344' = [28, 74, 54,020]
   const arr: u8[] = [];
-  const bytes = "11223344";
   let lengthBytes = 0;
-  for (let i = 0; i < bytes.length; i += 2) {
-    const byte = bytes.substr(i, 2);
+  for (let i = 0; i < dataStr.length; i += 2) {
+    const byte = dataStr.substr(i, 2);
     const value = parseInt(byte, 16);
     arr.push(u8(value));
     lengthBytes += 1;
diff --git a/tests/decoding.test.js b/tests/decoding.test.js
index 44c086d..26837b6 100644
--- a/tests/decoding.test.js
+++ b/tests/decoding.test.js
@@ -11,11 +11,11 @@ import {
     decodeObject,
     decodeArrayU8,
     decodeArray,
-    decodeAllInArray,
     decodeBytes,
-    decodeAllInObj,
-    decodeNestedObjs,
+    decodeRainCBOR_test,
     decodeArrayInArray,
+    decode,
+    decode_assertError,
 } from "../build/debug.js";
 
 let result;
@@ -73,6 +73,18 @@ describe("Decoding", () => {
         result = decodeObject()
         assert.equal(result, true);
     })
+    it("Test decode function", () => {
+        result = decode("0x010101")
+        assert.deepEqual(result, {});
+    })
+    it("Test decodeRainCBOR_test function", () => {
+        result = decodeRainCBOR_test("A3004411223344011BFFC21BBF86CC199B02706170706C69636174696F6E2F63626F72A3004412345678011BFFE5FFB4A3FF2CDE02706170706C69636174696F6E2F6A736F6E")
+        assert.deepEqual(result, true);
+    })
+    it("Test decode_assertError function when error", () => {
+        result = decode_assertError("0101")
+        assert.equal(result, false);
+    })
 })
 
 //
diff --git a/tests/encoding.test.js b/tests/encoding.test.js
index 9bf2d43..2be411f 100644
--- a/tests/encoding.test.js
+++ b/tests/encoding.test.js
@@ -41,8 +41,7 @@ let result;
 
 describe("Encoding", () => {
     it("Test encodeRainDocument function", () => {
-        result = encodeRainDocument();
-
+        result = encodeRainDocument("11223344");
         assert.equal(
             "a3004411223344011bffc21bbf86cc199b02706170706c69636174696f6e2f63626f72",
             buf2hex(result)
diff --git a/tests/rainCbor.test.js b/tests/rainCbor.test.js
index afe1435..008ae8c 100644
--- a/tests/rainCbor.test.js
+++ b/tests/rainCbor.test.js
@@ -1,24 +1,53 @@
-import { strict as assert } from "assert";
+import {strict as assert} from "assert";
 import {
-  decodeRainCBOR_test,
-  decode,
-  decode_assertError
+    decodeRainCBOR_test,
+    decode_assertError,
+    decodeRandomString,
+    decode
 } from "../build/debug.js";
 
 describe("Rain Cbor", () => {
-  it("Test rain cbor", () => {
+    it("Test rain cbor", () => {
 
-    const result = decodeRainCBOR_test();
-    assert.equal(result, true, "Failed when decoded a rain cbor sequence");
+        const result = decodeRainCBOR_test("A3004411223344011BFFC21BBF86CC199B02706170706C69636174696F6E2F63626F72A3004412345678011BFFE5FFB4A3FF2CDE02706170706C69636174696F6E2F6A736F6E");
+        assert.equal(result, true, "Failed when decoded a rain cbor sequence");
 
-    decode("A3004412345678011BFFE5FFB4A3FF2CDE026474657874");
-    decode("4f726465725f41");
-    decode("6F726465725F61");
+    });
 
-    const resultError = decode_assertError(
-        "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"
-    );
-    assert.equal(resultError, true);
+    it("Should return false for an invalid encoded rain sequence", () => {
 
-  });
+        const resultError = decode_assertError(
+            "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"
+        );
+        assert.equal(resultError, true);
+
+    });
+    it("Should returns error message for an invalid encoded rain sequence", () => {
+
+        const result = decodeRandomString(
+            "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"
+        );
+        assert.equal(result, 'DATA_BAD_FORMED');
+
+    });
+
+    it('should return false for an empty input string', () => {
+        const result = decodeRainCBOR_test("");
+        assert.equal(result, false);
+    });
+
+    it('should return false for a non-CBOR encoded string', () => {
+        const result = decodeRainCBOR_test('this is not CBOR encoded');
+        assert.equal(result, false);
+    });
+
+    it('should return "Data_Empty" if passed empty string', () => {
+        const result = decodeRandomString('');
+        assert.equal(result, 'DATA_EMPTY');
+    });
+
+    it('should check random string not cbor decoded', () => {
+        const result = decodeRandomString('Random not cbor-encoded string');
+        assert.equal(result, '[0,0,0,0,0,12,11,0,14,12,NO_VALUE_0,13,0,0,0]');
+    });
 });
\ No newline at end of file