promote the pyopenssl overlay to the very top

nixos/modules/overlays.nix

@@ -21,8 +21,6 @@ let
       # And explicitly configure it with our preferred version of Tahoe-LAFS.
       inherit tahoe-lafs;
     };
-
-    pyopenssl = python-self.callPackage ../pkgs/pyopenssl.nix { };
   };
 in
 self: super: {

nixos/openssl-111k.nix

@@ -9,4 +9,10 @@ self: super: rec {
     };
   });
   openssl = openssl_1_1;
+
+  python27 = super.python27.override (old: {
+    packageOverrides = python-self: python-super: {
+      pyopenssl = python-super.callPackage ./pkgs/pyopenssl.nix { };
+    };
+  });
 }

nixos/pkgs/pyopenssl.nix

-{ fetchPypi, pyopenssl }:
-pyopenssl.overrideAttrs (old: {
+{ stdenv
+, buildPythonPackage
+, fetchPypi
+, openssl
+, cryptography
+, pyasn1
+, idna
+, pytest
+, pretend
+, flaky
+, glibcLocales
+}:
+
+with stdenv.lib;
+
+
+let
+  # https://github.com/pyca/pyopenssl/issues/791
+  # These tests, we disable in the case that libressl is passed in as openssl.
+  failingLibresslTests = [
+    "test_op_no_compression"
+    "test_npn_advertise_error"
+    "test_npn_select_error"
+    "test_npn_client_fail"
+    "test_npn_success"
+    "test_use_certificate_chain_file_unicode"
+    "test_use_certificate_chain_file_bytes"
+    "test_add_extra_chain_cert"
+    "test_set_session_id_fail"
+    "test_verify_with_revoked"
+    "test_set_notAfter"
+    "test_set_notBefore"
+  ];
+
+  # these tests are extremely tightly wed to the exact output of the openssl cli tool,
+  # including exact punctuation.
+  failingOpenSSL_1_1Tests = [
+    "test_dump_certificate"
+    "test_dump_privatekey_text"
+    "test_dump_certificate_request"
+    "test_export_text"
+  ];
+
+  disabledTests = [
+    # https://github.com/pyca/pyopenssl/issues/692
+    # These tests, we disable always.
+    "test_set_default_verify_paths"
+    "test_fallback_default_verify_paths"
+    # https://github.com/pyca/pyopenssl/issues/768
+    "test_wantWriteError"
+  ] ++ (
+    optionals (hasPrefix "libressl" openssl.meta.name) failingLibresslTests
+  ) ++ (
+    optionals (versionAtLeast (getVersion openssl.name) "1.1") failingOpenSSL_1_1Tests
+  );
+
+  # Compose the final string expression, including the "-k" and the single quotes.
+  testExpression = optionalString (disabledTests != [])
+    "-k 'not ${concatStringsSep " and not " disabledTests}'";
+
+in
+
+
+buildPythonPackage rec {
+  pname = "pyOpenSSL";
   version = "20.0.1";
-  inherit (old) name;
+
   src = fetchPypi {
-    inherit name;
-    sha256 = "aeca66338f6de19d1aa46ed634c3b9ae519a64b458f8468aec688e7e3c20f201";
+    inherit pname version;
+    sha256 = "beca66338f6de19d1aa46ed634c3b9ae519a64b458f8468aec688e7e3c20f200";
   };
-})
+
+  outputs = [ "out" "dev" ];
+
+  checkPhase = ''
+    runHook preCheck
+    export LANG="en_US.UTF-8"
+    py.test tests ${testExpression}
+    runHook postCheck
+  '';
+
+  # Seems to fail unpredictably on Darwin. See http://hydra.nixos.org/build/49877419/nixlog/1
+  # for one example, but I've also seen ContextTests.test_set_verify_callback_exception fail.
+  doCheck = !stdenv.isDarwin;
+
+  nativeBuildInputs = [ openssl ];
+  propagatedBuildInputs = [ cryptography pyasn1 idna ];
+
+  checkInputs = [ pytest pretend flaky glibcLocales ];
+}