Menu
So when testing one of my reducers in a Preact(not much different to React while testing with JEST) based project, I got bumped into this issue:
Following output comes up when running jest test -
● should setup expect(received).toEqual(expected) Expected value to equal: {"ID": Any<String>, "active": true, "data": Any<Array>} Received: {"ID": "BysnEuMlm", "active": true, "data": [{"ID": "Hy7wMAz1lm", "code": "dat.fle", "label": "CRES/datum14.cdata", "name": "File", "status": "READY", "value": {"format": "cdata", "name": "datum14.cdata", "path": "CRES"}}, {"ID": "rkB7RMkeX", "code": "prp.kcv", "label": "3 folds", "name": "k-Fold Cross-Validation", "status": "READY", "value": "3"}, {"ID": "ByCmRfygQ", "code": "ats", "label": undefined, "name": " Best First + Cfs Subset Eval", "status": "READY", "value": {"evaluator": {"name": "CfsSubsetEval"}, "search": {"name": "BestFirst", "options": ["-D", "1", "-N", "5"]}, "use": true}}, {"ID": "HkmVAM1l7", "code": "lrn", "label": undefined, "name": "Naive Bayes", "status": "READY", "value": {"label": "Naive Bayes", "name": "bayes.NaiveBayes", "use": true}}], "output": {"format": "pipeline", "name": "jestReact.cpipe", "path": "/home/rupav/opensource/candis/CRES"}} Difference: - Expected + Received Object { - "ID": Any<String>, + "ID": "BysnEuMlm", "active": true, - "data": Any<Array>, + "data": Array [ + Object { + "ID": "Hy7wMAz1lm", + "code": "dat.fle", + "label": "CRES/datum14.cdata", + "name": "File", + "status": "READY", + "value": Object { + "format": "cdata", + "name": "datum14.cdata", + "path": "CRES", + }, + }, + Object { + "ID": "rkB7RMkeX", + "code": "prp.kcv", + "label": "3 folds", + "name": "k-Fold Cross-Validation", + "status": "READY", + "value": "3", + }, + Object { + "ID": "ByCmRfygQ", + "code": "ats", + "label": undefined, + "name": " Best First + Cfs Subset Eval", + "status": "READY", + "value": Object { + "evaluator": Object { + "name": "CfsSubsetEval", + }, + "search": Object { + "name": "BestFirst", + "options": Array [ + "-D", + "1", + "-N", + "5", + ], + }, + "use": true, + }, + }, + Object { + "ID": "HkmVAM1l7", + "code": "lrn", + "label": undefined, + "name": "Naive Bayes", + "status": "READY", + "value": Object { + "label": "Naive Bayes", + "name": "bayes.NaiveBayes", + "use": true, + }, + }, + ], + "output": Object { + "format": "pipeline", + "name": "jestReact.cpipe", + "path": "/home/rupav/opensource/candis/CRES", + }, } Following is the test case:
test('should setup ', () => { const state = documentProcessor( undefined, { type: ActionType.Asynchronous.READ_SUCCESS, payload: dokuments.active }) // expect(state.active.ID).toEqual(expect.any(String)) - Test case passes iff I run this test with this command only. expect(state.active).toEqual({ data: expect.any(Array), active: true, ID: expect.any(String), }) }) Since state gets changed while calling that reducer, I needed to use expect.any function, but as per the output, although types are same, test is not getting passed. Rather in expected its showing up Any<String>.
690
The expect function is used every time you want to test a value. You will rarely call expect by itself. Instead, you will use expect along with a "matcher" function to assert something about a value. expect(bestLaCroixFlavor()).
Expect. assertions(number) verifies that a certain number of assertions are called during a test. This is often useful when testing asynchronous code, in order to make sure that assertions in a callback actually got called. So to put in other words, expect.
Jest documentation reads: toBe just checks that a value is what you expect. It uses === to check strict equality.
In Jest you have to pass a function into expect(function). toThrow(<blank or type of error>) . Example: test("Test description", () => { const t = () => { throw new TypeError(); }; expect(t).
expect.toEqual checks for equality of state.active in your case. To achieve what you want, you have to make multiple expect statements:
expect(state.active.active).toEqual(true) expect(state.active.data).toEqual(expect.any(Array)) expect(state.active.ID).toEqual(expect.any(String)) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
