Add simple script for testing web API

This is not a comprehensive test, but does provide a way to easily
compare that what was originally fetched for a recipe from the API is
the same once it's been imported into a new instance using
import_layers.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

layerindex/tools/webapi-test.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+
+# Layerindex web API test utility
+
+# Copyright (C) 2019 Intel Corporation
+#
+# Licensed under the MIT license, see COPYING.MIT for details
+
+import sys
+import os
+import argparse
+import json
+import requests
+import subprocess
+import tempfile
+import shutil
+import re
+
+def compare_recipe(args):
+    tmpdir = tempfile.mkdtemp()
+    try:
+        def fetch_json(url, fn):
+            fetchurl = url + '/layerindex/api/recipes/?filter=pn:%s' % args.pn
+            print('getting %s' % fetchurl)
+            r = requests.get(fetchurl)
+            if not r.ok:
+                print('Request failed: %d: %s' % (r.status_code, r.text))
+                sys.exit(2)
+            jsdata = json.loads(r.text)
+            with open(os.path.join(tmpdir, fn), 'w') as f:
+                json.dump(jsdata, f, indent=4, sort_keys=True)
+                f.write('\n')
+
+        fetch_json(args.url1, 'file1')
+        fetch_json(args.url2, 'file2')
+
+        subprocess.call(['git', 'diff', '--no-index', os.path.join(tmpdir, 'file1'), os.path.join(tmpdir, 'file2')], shell=False)
+    finally:
+        shutil.rmtree(tmpdir)
+
+
+def main():
+    parser = argparse.ArgumentParser(description="github fetch utility",
+                                        epilog="Use %(prog)s <subcommand> --help to get help on a specific command")
+    #parser.add_argument('-d', '--debug', help='Enable debug output', action='store_true')
+    subparsers = parser.add_subparsers(title='subcommands', metavar='<subcommand>')
+    subparsers.required = True
+
+    parser_compare_recipe = subparsers.add_parser('compare-recipe',
+                                                  help='Compare recipe JSON from two different layer index instances',
+                                                  description='Compares recipe JSON from two different layer index instances')
+    parser_compare_recipe.add_argument('url1', help='First layer index URL to fetch from')
+    parser_compare_recipe.add_argument('url2', help='Second layer index URL to fetch from')
+    parser_compare_recipe.add_argument('pn', help='Recipe name to compare')
+    parser_compare_recipe.set_defaults(func=compare_recipe)
+
+    args = parser.parse_args()
+
+    ret = args.func(args)
+
+    return ret
+
+
+if __name__ == "__main__":
+    try:
+        ret = main()
+    except Exception:
+        ret = 1
+        import traceback
+        traceback.print_exc()
+    sys.exit(ret)