testenv: Add test for handling of no_proxy environment variable

* testenv/Test-no_proxy-env.py: Added new test for no_proxy env
* testenv/Makefile.am: Added the new test to Makefile

Added new test with 5 cases, which are testing various combinations
of no_proxy environment variable definition and requested URLs.
The test is skipped if the system does not support resolution of
localhost subdomains to lcalhost address.

Signed-off-by: Tomas Hozza <thozza@redhat.com>

testenv/Makefile.am

@@ -116,6 +116,7 @@ if HAVE_PYTHON3
     Test--rejected-log.py                           \
     Test-reserved-chars.py                          \
     Test--spider-r.py                               \
+    Test-no_proxy-env.py                            \
     $(METALINK_TESTS)
 
 endif

testenv/Test-no_proxy-env.py

@@ -0,0 +1,160 @@
+#!/usr/bin/env python3
+import socket
+from sys import exit
+from test.http_test import HTTPTest
+from test.base_test import HTTP
+from misc.wget_file import WgetFile
+
+"""
+    This test ensures, that domains with and without leftmost dot defined in
+    no_proxy environment variable are accepted by wget. The idea is to use
+    non-existing proxy server address and detect whether files are downloaded
+    when proxy settings are omitted based on no_proxy environment variable
+    value.
+
+    current wget's behavior:
+    - "no_proxy=.mit.edu"
+      - will match the domain and subdomains e.g. "www.mit.edu" or "www.subdomain.mit.edu" (Case #4)
+      - will NOT match the host "mit.edu" (Case #3)
+    - "no_proxy=mit.edu"
+      - will match the domain and subdomains e.g. "www.mit.edu" or "www.subdomain.mit.edu" (Case #2)
+      - will match the host "mit.edu" (Case #1)
+    - downside: can not match only the host
+"""
+
+# Check whether the system supports translating localhost subdomains
+# to localhost address and if not, skip it.
+hostnames_to_check = [
+    "working1.localhost",
+    "working2.localhost",
+    "www.working1.localhost",
+    "www.working2.localhost",
+]
+for hostname in hostnames_to_check:
+    try:
+        ip = socket.gethostbyname(hostname)
+    except socket.gaierror as _:
+        # resolution of the name failes
+        # return value 77 -> SKIP
+        exit(77)
+
+# File Definitions
+File1 = "Would you like some Tea?"
+File2 = "With lemon or cream?"
+
+A_File = WgetFile ("File1", File1)
+B_File = WgetFile ("File2", File2)
+
+WGET_URLS = [["File1", "File2"]]
+WGET_ENVS = {
+    "http_proxy": "nonexisting.localhost:8080",
+    "no_proxy": "working1.localhost,.working2.localhost"
+}
+
+Servers = [HTTP]
+Files = [[A_File, B_File]]
+
+ExpectedReturnCodeWorking = 0
+ExpectedReturnCodeNotWorking = 4  # network error (non-existing proxy address)
+
+ExpectedDownloadedFilesWorking = [A_File, B_File]
+
+# Pre and Post Test Hooks
+test_options = {
+    "Urls"                : WGET_URLS,
+    "EnvironmentVariables": WGET_ENVS
+}
+post_test_working = {
+    "ExpectedFiles"     : ExpectedDownloadedFilesWorking,
+    "ExpectedRetcode"   : ExpectedReturnCodeWorking
+}
+post_test_not_working = {
+    "ExpectedRetcode"   : ExpectedReturnCodeNotWorking
+}
+
+# Case #1:
+# - Requested domain matches exactly the domain definition in no_proxy.
+# - Domain definition in no_proxy is NOT dot-prefixed
+# Expected result: proxy settings don't apply and files are downloaded.
+pre_case_1 = {
+    "ServerFiles"       : Files,
+    "Domains"           : ["working1.localhost"]
+}
+
+err_case_1 = HTTPTest (
+    pre_hook=pre_case_1,
+    test_params=test_options,
+    post_hook=post_test_working,
+    protocols=Servers
+).begin ()
+
+# Case #2:
+# - Requested domain is sub-domain of a domain definition in no_proxy.
+# - Domain definition in no_proxy is NOT dot-prefixed
+# Expected result: proxy settings don't apply and files are downloaded.
+pre_case_2 = {
+    "ServerFiles"       : Files,
+    "Domains"           : ["www.working1.localhost"]
+}
+
+err_case_2 = HTTPTest (
+    pre_hook=pre_case_2,
+    test_params=test_options,
+    post_hook=post_test_working,
+    protocols=Servers
+).begin ()
+
+# Case #3:
+# - Requested domain matches exactly the domain definition in no_proxy,
+#   except for the leftmost dot (".") in no_proxy domain definition.
+# - Domain definition in no_proxy IS dot-prefixed
+# Expected result: proxy settings apply and files are downloaded. This is
+#                  due to the mismatch in leftmost dot.
+# NOTE: This is inconsistent with curl's behavior, but has less drawbacks.
+pre_case_3 = {
+    "ServerFiles"       : Files,
+    "Domains"           : ["working2.localhost"]
+}
+
+err_case_3 = HTTPTest (
+    pre_hook=pre_case_3,
+    test_params=test_options,
+    post_hook=post_test_not_working,
+    protocols=Servers
+).begin ()
+
+# Case #4:
+# - Requested domain is sub-domain of a domain definition in no_proxy.
+# - Domain definition in no_proxy IS dot-prefixed
+# Expected result: proxy settings don't apply and files are downloaded.
+pre_case_4 = {
+    "ServerFiles"       : Files,
+    "Domains"           : ["www.working2.localhost"]
+}
+
+err_case_4 = HTTPTest (
+    pre_hook=pre_case_4,
+    test_params=test_options,
+    post_hook=post_test_working,
+    protocols=Servers
+).begin ()
+
+# Case #5
+# - Requested domain does not match a domain definition in no_proxy.
+# - Requested domain is NOT sub-domain of a domain definition in no_proxy.
+# Expected result: proxy settings apply and files are NOT downloaded due to
+#                  network error when using proxy with non-existing URL.
+pre_case_5 = {
+    "ServerFiles"       : Files,
+    "Domains"           : ["www.example.localhost"]
+}
+
+err_case_5 = HTTPTest (
+    pre_hook=pre_case_5,
+    test_params=test_options,
+    post_hook=post_test_not_working,
+    protocols=Servers
+).begin ()
+
+# Combine error codes from all test cases
+exit (max(err_case_1, err_case_2, err_case_3, err_case_4, err_case_5))