ReadonlycallsA getter that returns a copy of the internal array used to track calls to the mock. Each entry in the array is an object with the following properties.
This function returns the number of times that this mock has been invoked. This
function is more efficient than checking ctx.calls.length because ctx.calls is a getter that creates a copy of the internal call tracking array.
The number of times that this mock has been invoked.
This function is used to change the behavior of an existing mock.
The following example creates a mock function using t.mock.fn(), calls the
mock function, and then changes the mock implementation to a different function.
test('changes a mock behavior', (t) => {
let cnt = 0;
function addOne() {
cnt++;
return cnt;
}
function addTwo() {
cnt += 2;
return cnt;
}
const fn = t.mock.fn(addOne);
assert.strictEqual(fn(), 1);
fn.mock.mockImplementation(addTwo);
assert.strictEqual(fn(), 3);
assert.strictEqual(fn(), 5);
});
The function to be used as the mock's new implementation.
This function is used to change the behavior of an existing mock for a single
invocation. Once invocation onCall has occurred, the mock will revert to
whatever behavior it would have used had mockImplementationOnce() not been
called.
The following example creates a mock function using t.mock.fn(), calls the
mock function, changes the mock implementation to a different function for the
next invocation, and then resumes its previous behavior.
test('changes a mock behavior once', (t) => {
let cnt = 0;
function addOne() {
cnt++;
return cnt;
}
function addTwo() {
cnt += 2;
return cnt;
}
const fn = t.mock.fn(addOne);
assert.strictEqual(fn(), 1);
fn.mock.mockImplementationOnce(addTwo);
assert.strictEqual(fn(), 3);
assert.strictEqual(fn(), 4);
});
The function to be used as the mock's implementation for the invocation number specified by onCall.
OptionalonCall: numberThe invocation number that will use implementation. If the specified invocation has already occurred then an exception is thrown.
The
MockFunctionContextclass is used to inspect or manipulate the behavior of mocks created via theMockTrackerAPIs.Since
v19.1.0, v18.13.0