Correctly handle -m and -k flags

Fixes #36.

Author: wbolster

python-pytest.el

@@ -128,8 +128,8 @@ When non-nil only ‘test_foo()’ will match, and nothing else."
     ("-s" "no output capture" "--capture=no")
     (python-pytest:-v)]]
   ["Selection, filtering, ordering"
-   [("-k" "only names matching expression" "-k=")
-    ("-m" "only marks matching expression" "-m=")
+   [(python-pytest:-k)
+    (python-pytest:-m)
     "                                          "] ;; visual alignment
    [("--dm" "run doctests" "--doctest-modules")
     ("--nf" "new first" "--new-first")
@@ -441,6 +441,20 @@ When present ON-REPLACEMENT is substituted, else OFF-REPLACEMENT is appended."
           (format "%s %s" option it)))
    args))
 
+(transient-define-argument python-pytest:-k ()
+  :description "only names matching expression"
+  :class 'transient-option
+  :argument "-k"
+  :allow-empty nil
+  :key "-k")
+
+(transient-define-argument python-pytest:-m ()
+  :description "only marks matching expression"
+  :class 'transient-option
+  :argument "-m"
+  :allow-empty nil
+  :key "-m")
+
 (transient-define-argument python-pytest:-v ()
   :description "verbosity"
   :class 'transient-switches