t.ctx Property

References the test context object. Each test has a test context object of its own. Store data within the test context object to share information between test hooks and the test body.

t.ctx → Object

You can completely redefine t.ctx or simply add a property to the object:

fixture`TestController.ctx`
    .beforeEach(async t => {
        t.ctx.someProp = 123;
    });

test('Check context', async t => {
    await t.expect(t.ctx.someProp).eql(123); // > 123
}).after(async t => {
    await t.expect(t.ctx.someProp).eql(123); // > 123
});