Rodolfo Hansen
A collection of slides I have generated for some of the talks / workshops I have created.
How to be an expert test writer.
It's harder than you think
Good unit tests are:
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Fast (milliseconds)
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Repeatable (run multiple times)
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Self Contained (does not need other tests)
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Precise (pin pointing target)
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Resilient (unaffected by other changes)
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Sensitive (avoids false negatives)
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Specific (avoids false positives)
[Test]
public void testMeasurementSupervisor_patientAndDevice_loadsWarning(){
Mock<Person>patient = new Mock<Person>(); // Self Contained
Mock<Device>heartRateMonitor = new Mock<HeartRateMonitor>(); // Fast
patient.Setup(p => p.isMale()).Returns(() => true); // Precise
heartRateMonitor.Setup(hr => hr.heartRateOver5Minutes()).Returns(() => MAX_MALE_HEARTRATE + 10);
bool sexDinstinction = loadSexDistinctionSettings(); // Repeatable
MeasumentSupervisor ms = new MeasumentSupervisor<HeartRateMonitor>(sexDinstinction, MAX_MAKE_HEARTRATE); // Resilient
AnalisisResult analisysResult = ms.analize(patient, heartRateMonitor);
Assert.isNotNull(analisysResult);
if (sexDinstinction) {
Assert.isTrue(analisysResult.Critical); // Sensitive
} else {
Assert.isTrue(analisysResult.Warning); // Specific
}
}
Ensuring you apply the criteria
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Write testable code (test driven development)
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Checklists (simple and effective)
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Code coverage (branch coverage / statement coverage)
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Property based testing (contracts)
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Mutation Testing (specificity)
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Static Analysis (tests are code)
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Capture Statistics (beyond pass/fail)
How to be an expert test writer.
By Rodolfo Hansen
