Three practical approaches to unit testing NgRx selectors in Angular applications: the default approach (calling selectors with crafted state), snapshot testing (ideal for simple selectors without logic), and the projector function approach (for selectors with complex state dependencies or logic). Factory functions are recommended for setting up isolated test state to avoid fragile tests. The projector function, built into NgRx, lets you bypass dependent selectors and pass their outputs directly, reducing setup complexity.
Table of contents
What exactly is a selectorKnowing which selectors to testSetting up test state with factory functionsTesting approach #1: “Default”Testing Approach #2: SnapshotsTesting Approach #3: ProjectorConclusionNot to miss2 Impressions