tests: add test for Flatpak-Upgrade-From header on install vs update

Add an integration test that verifies the Flatpak-Upgrade-From HTTP
header is correctly sent during update operations but absent during
fresh installs. This header is used by Flathub to distinguish updates
from new installs in download statistics.

To support the test, extend web-server.py to optionally log Flatpak-*
request headers to a separate file.

tests/meson.build

@@ -409,6 +409,7 @@ tests = {
   'extra-data': {'wrap': ['user', 'system']},
   'preinstall': {},
   'run-custom': {'wrap': ['user', 'system']},
+  'upgrade-from-header': {'wrap': ['user', 'system', 'system-norevokefs']},
 }
 
 wrapped_tests = []

tests/test-upgrade-from-header.sh

@@ -0,0 +1,60 @@
+#!/bin/bash
+
+set -euo pipefail
+
+. "$(dirname "$0")"/libtest.sh
+
+skip_without_bwrap
+skip_revokefs_without_fuse
+
+echo "1..4"
+
+# Override the httpd function to enable header logging before setup_repo calls
+# it. The web-server.py will log Flatpak-Ref and Flatpak-Upgrade-From headers
+# to httpd-headers-log.
+httpd () {
+    if [ $# -eq 0 ] ; then
+        set web-server.py repos "$(pwd)"/httpd-headers-log
+    fi
+
+    COMMAND=$1
+    shift
+
+    rm -f httpd-pipe
+    mkfifo httpd-pipe
+    PYTHONUNBUFFERED=1 "$(dirname "$0")"/$COMMAND "$@" 3> httpd-pipe 2>&1 | tee -a httpd-log >&2 &
+    read < httpd-pipe
+}
+
+touch httpd-headers-log
+
+setup_repo
+
+truncate -s 0 httpd-headers-log
+
+install_repo
+
+APP_REF="app/org.test.Hello/${ARCH}/master"
+
+assert_not_file_has_content httpd-headers-log "Flatpak-Upgrade-From"
+
+ok "no Flatpak-Upgrade-From header on fresh install"
+
+assert_file_has_content httpd-headers-log "Flatpak-Ref: ${APP_REF}"
+
+ok "Flatpak-Ref header sent on fresh install"
+
+INSTALLED_COMMIT=$(${FLATPAK} ${U} info --show-commit org.test.Hello)
+
+make_updated_app
+truncate -s 0 httpd-headers-log
+
+${FLATPAK} ${U} update -y org.test.Hello >&2
+
+assert_file_has_content httpd-headers-log "Flatpak-Upgrade-From: ${INSTALLED_COMMIT}"
+
+ok "Flatpak-Upgrade-From header sent with correct commit hash on update"
+
+assert_file_has_content httpd-headers-log "Flatpak-Ref: ${APP_REF}"
+
+ok "Flatpak-Ref header sent on update"

tests/web-server.py

@@ -15,6 +15,8 @@ from io import BytesIO
 import sys
 
 class RequestHandler(http_server.SimpleHTTPRequestHandler):
+    headers_log_file = None
+
     def handle_tokens(self):
         need_token_path = self.translate_path(self.path) + ".need_token"
         if os.path.isfile(need_token_path):
@@ -34,14 +36,26 @@ class RequestHandler(http_server.SimpleHTTPRequestHandler):
                 return True
         return False
 
+    def log_flatpak_headers(self):
+        if self.headers_log_file is None:
+            return
+
+        for name in ("Flatpak-Ref", "Flatpak-Upgrade-From", "Flatpak-Is-Update"):
+            value = self.headers.get(name)
+            if value is not None:
+                with open(self.headers_log_file, 'a+') as f:
+                    f.write("%s: %s\n" % (name, value))
+
     def do_GET(self):
+        self.log_flatpak_headers()
         if self.handle_tokens():
             return None
         self.headers.__delitem__("If-Modified-Since")
         return super().do_GET()
 
-def run(dir):
+def run(dir, headers_log=None):
     RequestHandler.protocol_version = "HTTP/1.0"
+    RequestHandler.headers_log_file = headers_log
     httpd = http_server.HTTPServer( ("127.0.0.1", 0), RequestHandler)
     host, port = httpd.socket.getsockname()[:2]
     with open("httpd-port", 'w') as file:
@@ -59,7 +73,10 @@ def run(dir):
 
 if __name__ == '__main__':
     dir = None
+    headers_log = None
     if len(sys.argv) >= 2 and len(sys.argv[1]) > 0:
         dir = sys.argv[1]
+    if len(sys.argv) >= 3 and len(sys.argv[2]) > 0:
+        headers_log = sys.argv[2]
 
-    run(dir)
+    run(dir, headers_log)