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June 26, 2023 18:20
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| /* | |
| * This code snippet is an extract of a private codebase. Though it relies on many dependencies to | |
| * the rest of the codebase, I believe that the code carries enough intension so that one can get | |
| * the overall idea (see: https://blog.mathieueveillard.com/monkey-testing-et-property-based-testing-une-exploration) | |
| */ | |
| import fc from "fast-check"; | |
| const ALL_REDUCERS: HasName<Reducer<ApplicationState>>[] = [ | |
| withName("selectPhotograph")(pickRandomIndex(getNumberOfPhotographs)(selectionReducers.selectPhotograph)), | |
| withName("selectPreviousPhotograph")(selectionReducers.selectPreviousPhotograph), | |
| withName("selectNextPhotograph")(selectionReducers.selectNextPhotograph), | |
| withName("selectLowerPhotograph")(selectionReducers.selectLowerPhotograph), | |
| withName("selectUpperPhotograph")(selectionReducers.selectUpperPhotograph), | |
| withName("selectFirstPhotograph")(selectionReducers.selectFirstPhotograph), | |
| withName("selectLastPhotograph")(selectionReducers.selectLastPhotograph), | |
| withName("resetSelection")(selectionReducers.resetSelection), | |
| withName("selectDeletedPhotograph")(pickRandomIndex(getNumberOfDeletedPhotographs)(trashBinSelectionReducers.selectDeletedPhotograph)), | |
| withName("selectPreviousDeletedPhotograph")(trashBinSelectionReducers.selectPreviousDeletedPhotograph), | |
| withName("selectNextDeletedPhotograph")(trashBinSelectionReducers.selectNextDeletedPhotograph), | |
| withName("selectFirstDeletedPhotograph")(trashBinSelectionReducers.selectFirstDeletedPhotograph), | |
| withName("selectLastDeletedPhotograph")(trashBinSelectionReducers.selectLastDeletedPhotograph), | |
| withName("resetDeletedPhotographsSelection")(trashBinSelectionReducers.resetDeletedPhotographsSelection), | |
| withName("moveDown")(photographReducers.moveDown), | |
| withName("moveUp")(photographReducers.moveUp), | |
| withName("moveToFirst")(photographReducers.moveToFirst), | |
| withName("moveToLast")(photographReducers.moveToLast), | |
| withName("deleteSelection")(photographReducers.deleteSelection), | |
| withName("cancel")(cancellationReducers.cancel), | |
| withName("restorePhotograph")(trashBinReducers.restorePhotograph), | |
| withName("zoomIn")(zoomReducers.zoomIn), | |
| withName("zoomOut")(zoomReducers.zoomOut), | |
| withName("zoomMin")(zoomReducers.zoomMin), | |
| withName("zoomMax")(zoomReducers.zoomMax), | |
| withName("resetZoom")(zoomReducers.resetZoom), | |
| withName("enterSlideshow")(focusReducers.enterSlideshow), | |
| withName("exitSlideshow")(focusReducers.exitSlideshow), | |
| withName("enterSlideshowAtIndex")(pickRandomIndex(getNumberOfPhotographs)(focusReducers.enterSlideshowAtIndex)), | |
| withName("toggleSlideshow")(focusReducers.toggleSlideshow), | |
| withName("toggleTrashBin")(focusReducers.toggleTrashBin), | |
| ]; | |
| describe("Monkey testing", () => { | |
| test("Random actions that preserve the overall number of photographs", () => { | |
| fc.assert( | |
| fc.property( | |
| fc.nat({ max: 10 }), | |
| fc.nat({ max: 10 }), | |
| (numberOfPhotographs, numberOfDeletedPhotographs) => { | |
| // GIVEN | |
| const state = mockState<ApplicationState>({ | |
| photographs: arrayOfPhotographs(numberOfPhotographs), | |
| trashBin: arrayOfPhotographs(numberOfDeletedPhotographs), | |
| selection: "NO_INDEX", | |
| trashBinSelection: "NO_INDEX", | |
| cancellation: "NOTHING_TO_CANCEL", | |
| focus: "THUMBNAILS", | |
| zoom: 5, | |
| }); | |
| const numberOfActions = 100; | |
| // WHEN | |
| const nextState = repeat<ApplicationState>(numberOfActions)( | |
| pickRandomReducer(ALL_REDUCERS) | |
| )(state); | |
| // THEN | |
| return ( | |
| getNumberOfPhotographs(nextState) + | |
| getNumberOfDeletedPhotographs(nextState) === | |
| getNumberOfPhotographs(state) + // | |
| getNumberOfDeletedPhotographs(state) | |
| ); | |
| } | |
| ) | |
| ); | |
| }); | |
| }); |
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