In order to serve you well, Karma needs to know about your project. That's done through a configuration file.
For an example file, see test/client/karma.conf.js which contains most of the options.
You can write the config file by hand or copy paste it from another project.
A third way is to use karma init
to generate it.
# This will ask you a few questions and generate a new config file
# called my.conf.js
$ karma init my.conf.js
When starting Karma, you can pass a path to the configuration file as an argument.
By default, Karma will look for karma.conf.js
in the current directory.
# Start Karma using your configuration
$ karma start my.conf.js
For more info about configuration file, see the configuration file docs.
Some of the configurations can be specified as a command line argument, which overrides the configuration from the config file.
Try karma start --help
if you want to see all available options.