granted: add functional tests for assume and assumego

Address reviewer feedback: verify assume and assumego commands work
instead of just checking file existence.

Author: emmanuel.john

Formula/g/granted.rb

@@ -31,8 +31,9 @@ def install
     output = shell_output("#{bin}/granted auth configure 2>&1", 1)
     assert_match "[✘] please provide a url argument", output
 
-    assert_path_exists bin/"assume"
-    assert_path_exists bin/"assumego"
+    ENV["GRANTED_ALIAS_CONFIGURED"] = "true"
+    assert_match version.to_s, shell_output("#{bin}/assume --version")
+    assert_match version.to_s, shell_output("#{bin}/assumego --version")
     assert_path_exists bin/"assume.fish"
   end
 end