Rewrite making test certificates (#393)

Also updates obsolete curl dependencies with zlib.

tests/exec.py

@@ -0,0 +1,43 @@
+#!/usr/bin/python3
+"""Implementation of a single ctest script."""
+
+import sys
+import subprocess
+
+
+def parse(value):
+    """Read parameter from file."""
+    prefix = 'FILE '
+    if value.startswith(prefix):
+        with open(value[len(prefix):], mode="r", encoding="utf-8") as file:
+            return file.read().strip()
+    return value
+
+
+def main() -> None:
+    """Run osslsigncode with its options."""
+    if len(sys.argv) > 1:
+        try:
+            params = map(parse, sys.argv[1:])
+            proc = subprocess.run(params, check=True)
+            sys.exit(proc.returncode)
+        except Exception as err: # pylint: disable=broad-except
+            # all exceptions are critical
+            print(err, file=sys.stderr)
+    else:
+        print("Usage:\n\t{} COMMAND [ARG]...'".format(sys.argv[0]), file=sys.stderr)
+    sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()
+
+
+# pylint: disable=pointless-string-statement
+"""Local Variables:
+    c-basic-offset: 4
+    tab-width: 4
+    indent-tabs-mode: nil
+End:
+    vim: set ts=4 expandtab:
+"""