How to mock static methods?

[davcrash]

I don't know how to mock static methods and i would like to know if you have any example or i have to fix mi code to works without static methods.

Thanks.

[srawlins]

There is no way to override a class's static method. Depending on your use case, you can wrap the static methods with a class and instance methods, like in the process package, or in the file package.

[davcrash]

@srawlins Can you show me an example, please?

[srawlins]

E.g. Process.runSync, is static.

Refactor this code:

class DirectoryLister {
  ProcessResult list(String directory) => Process.runSync('ls', [directory]);
}

to

class DirectoryLister {
  final ProcessManager processManager;
  DirectoryLister({ProcessManager processManager}) :
      this.processManager = processManager ?? ProcessManager;

  ProcessResult list(String directory) => processManager.runSync('ls', [directory]);
}

class ProcessManager {
  ProcessResult runSync(String command, List<String> args) =>
      Process.runSync(command, args);
}

Then in tests, you can create a MockProcessManager, and stub its runSync instance method. In real code, no need to fuss with or pass a ProcessManager in code that uses DirectoryLister. In tests, you create and pass a mock as the ProcessManager.

[davcrash]

Thanks, I'm going to refactor my code.

[haashem]

The other approach is to inject static methods to your class, instead of creating a wrapper around it:

class DirectoryLister {

void Function(String, List<Directory>) runSync;
DirectoryLister(this.runSync);

ProcessResult list(String directory) => runSync('ls', [directory]);

so in the test you when you create a mock of DirectoryLister, you can pass an stubbed method.