angularjs - Directive got called multiple times when executing unit tests -

i'm facing strange issue , hope met same problem before, can solving it.

what have:

• a 3rd party directive
• my custom directive (view uses 3rd party directive)
• unit tests (for other components well, around 300 unit tests)

my directive uses 3rd party directive within template way:

<3rd-party-directive value="bindedvalue" style="display:none;"></3rd-party-directive>  <div>{{producedvalue}}</div> 

so nothing magic going there. have unit tests custom directive (6 test case).

the problem:

• 1. if run unit tests custom directives (6 unit test), costs:
     • 0.007 sec
• 2. if run unit tests without custom directives unit tests (300 unit test), costs:
     • 2.3 sec
• 3. if run unit tests custom directives (306 unit test), costs:
     • 240 sec.

does meet problem before? dont want show code because it's not how implemented code. different going on here...

notes:

i run tests karma + jasmine. karma uses 100% cpu when 2nd case. when in begining of executecution fast later on it's increasingly slowing down. like:

1 - 80 unit tests --> 2 sec

81 - 120 unit tests --> 30 sec

121- 180 unit tests --> 90 sec

181- 300 unit tests --> 240 sec (here every unit test costs ~1 second...)

update

i made console.log inside custom directive , seems got called ~600 times!!! why , how? thought unit tests sandboxed-like, each 'describe' block has own sandbox.