tests/nixos/fetch-git: Factor out gitea repo module

tests/nixos/fetch-git/testsupport/gitea-repo.nix

@@ -0,0 +1,51 @@
+{ lib, ... }:
+let
+  inherit (lib) mkOption types;
+
+  testCaseExtension = { config, ... }: {
+    setupScript = ''
+      repo = Repo("${config.name}")
+    '';
+  };
+in
+{
+  options = {
+    testCases = mkOption {
+      type = types.listOf (types.submodule testCaseExtension);
+    };
+  };
+  config = {
+    setupScript = ''
+      class Repo:
+        """
+        A class to create a git repository on the gitea server and locally.
+        """
+        def __init__(self, name):
+          self.name = name
+          self.path = "/tmp/repos/" + name
+          self.remote = "http://gitea:3000/test/" + name
+          self.remote_ssh = "ssh://gitea/root/" + name
+          self.git = f"git -C {self.path}"
+          self.create()
+
+        def create(self):
+          # create ssh remote repo
+          gitea.succeed(f"""
+            git init --bare -b main /root/{self.name}
+          """)
+          # create http remote repo
+          gitea.succeed(f"""
+            curl --fail -X POST http://{gitea_admin}:{gitea_admin_password}@gitea:3000/api/v1/user/repos \
+              -H 'Accept: application/json' -H 'Content-Type: application/json' \
+              -d {shlex.quote( f'{{"name":"{self.name}", "default_branch": "main"}}' )}
+          """)
+          # setup git remotes on client
+          client.succeed(f"""
+            mkdir -p {self.path} \
+            && git init -b main {self.path} \
+            && {self.git} remote add origin {self.remote} \
+            && {self.git} remote add origin-ssh root@gitea:{self.name}
+          """)
+    '';
+  };
+}