From aae7a2df94c2a31bdeae7629190fc7de394d37ff Mon Sep 17 00:00:00 2001
From: Aleksei Androsov <aandrosov@yandex-team.ru>
Date: Mon, 29 Apr 2024 13:36:25 +0300
Subject: [PATCH] Add jest matchers for gzip (#61)

---
 jest.config.js           |  4 ++++
 tests/expect.js          | 19 +++++++++++++++++++
 tests/http_block.test.js |  5 ++---
 tests/request.test.js    | 16 +++++-----------
 4 files changed, 30 insertions(+), 14 deletions(-)
 create mode 100644 tests/expect.js

diff --git a/jest.config.js b/jest.config.js
index 45d4e10..f8986e7 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -1,9 +1,13 @@
 module.exports = {
     coveragePathIgnorePatterns: [
         '/node_modules/',
+        '/tests/expect.js',
         '/tests/server.js',
         '/tests/helpers.js',
     ],
+    setupFilesAfterEnv: [
+        './tests/expect.js',
+    ],
     testEnvironment: 'node',
     testRunner: 'jest-circus/runner',
 };
diff --git a/tests/expect.js b/tests/expect.js
new file mode 100644
index 0000000..18c7aab
--- /dev/null
+++ b/tests/expect.js
@@ -0,0 +1,19 @@
+const { gunzipSync } = require( 'node:zlib' );
+
+expect.extend( {
+    toBeValidGzip( received ) {
+        //  http://www.zlib.org/rfc-gzip.html#header-trailer
+        //  2.3.1. Member header and trailer
+        //  These have the fixed values ID1 = 31 (0x1f), ID2 = 139 (0x8b), to identify the file as being in gzip format.
+        return {
+            message: () => `incorrect header check for ${ received }`,
+            pass: received.slice( 0, 2 ).equals( Buffer.from( '1f8b', 'hex' ) ),
+        };
+    },
+    toHaveUngzipValue( received, value ) {
+        return {
+            message: () => `expected ${ received } to be ${ value }`,
+            pass: gunzipSync( received ).toString( 'utf-8' ) === value,
+        };
+    },
+} );
diff --git a/tests/http_block.test.js b/tests/http_block.test.js
index 296504c..e76e64c 100644
--- a/tests/http_block.test.js
+++ b/tests/http_block.test.js
@@ -9,7 +9,6 @@ const Server = require( './server' );
 const { get_path, get_result_block } = require( './helpers' );
 
 const strip_null_and_undefined_values = require( '../lib/strip_null_and_undefined_values' );
-const { gunzipSync } = require( 'node:zlib' );
 
 //  ---------------------------------------------------------------------------------------------------------------  //
 
@@ -857,9 +856,9 @@ describe( 'http', () => {
 
             expect( spy ).toHaveBeenCalledTimes( 1 );
             const body = spy.mock.calls[ 0 ][ 2 ];
-            expect( body.slice( 0, 2 ).equals( Buffer.from( '1f8b', 'hex' ) ) ).toBe( true );
+            expect( body ).toBeValidGzip();
             expect( body ).toHaveLength( 34 );
-            expect( gunzipSync( body ).toString( 'utf-8' ) ).toBe( 'Привет!' );
+            expect( body ).toHaveUngzipValue( 'Привет!' );
         } );
     } );
 
diff --git a/tests/request.test.js b/tests/request.test.js
index 41b8c3e..86345ce 100644
--- a/tests/request.test.js
+++ b/tests/request.test.js
@@ -4,7 +4,7 @@ const path_ = require( 'path' );
 const fs_ = require( 'fs' );
 const http_ = require( 'http' );
 const https_ = require( 'https' );
-const { gzipSync, gunzipSync } = require( 'node:zlib' );
+const { gzipSync } = require( 'node:zlib' );
 const { compress } = require( '@fengkx/zstd-napi' );
 const { Duplex } = require( 'stream' );
 
@@ -378,12 +378,9 @@ describe( 'request', () => {
             expect( req.headers ).toHaveProperty( 'transfer-encoding', 'chunked' );
             expect( req.headers ).not.toHaveProperty( 'content-length' );
 
-            //  http://www.zlib.org/rfc-gzip.html#header-trailer
-            //  2.3.1. Member header and trailer
-            //  These have the fixed values ID1 = 31 (0x1f), ID2 = 139 (0x8b), to identify the file as being in gzip format.
-            expect( body.slice( 0, 2 ).equals( Buffer.from( '1f8b', 'hex' ) ) ).toBe( true );
+            expect( body ).toBeValidGzip();
             expect( body ).toHaveLength( 77 );
-            expect( gunzipSync( body ).toString( 'utf-8' ) ).toBe( BODY );
+            expect( body ).toHaveUngzipValue( BODY );
         } );
 
         it.each( [ 'POST' ] )( '%j, body_compress with options', async ( method ) => {
@@ -412,12 +409,9 @@ describe( 'request', () => {
             expect( req.headers ).toHaveProperty( 'transfer-encoding', 'chunked' );
             expect( req.headers ).not.toHaveProperty( 'content-length' );
 
-            //  http://www.zlib.org/rfc-gzip.html#header-trailer
-            //  2.3.1. Member header and trailer
-            //  These have the fixed values ID1 = 31 (0x1f), ID2 = 139 (0x8b), to identify the file as being in gzip format.
-            expect( body.slice( 0, 2 ).equals( Buffer.from( '1f8b', 'hex' ) ) ).toBe( true );
+            expect( body ).toBeValidGzip();
             expect( body ).toHaveLength( 134 );
-            expect( gunzipSync( body ).toString( 'utf-8' ) ).toBe( BODY );
+            expect( body ).toHaveUngzipValue( BODY );
         } );
 
         describe( 'errors', () => {