decks: Go write tests using using pragmatic best practices

Signed-off-by: Edward Haas <[email protected]>

Author: EdDev

decks/go_write_tests_using_pragmatic_best_practices/cat_glasses.jpg

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+# Go Write Tests
+using Pragmatic Best Practices
+
+Edward Haas, @redhat <!-- .element: style="position: absolute; left: 0; top: 100%; font-size: 0.6em" -->
+[email protected] <!-- .element: style="position: absolute; left: 0; top: 120%; font-size: 0.6em" -->
+
+---
+
+# /me 
+
+---
+
+# Testing
+
+Why?
+
+Note: Because we are not prefect!
+
+---
+
+# Testing Levels
+
+- Unit
+- Integration
+- System
+
+Note:
+We can also consider compilation of typed languages and linters as an
+early development testing level.
+
+Most practices should fit them all.
+
+---
+
+# Test Definitions 
+
+--
+
+# Test Format <!-- .element: style="font-size: 1.8em" -->
+
+- Setup
+- Exercise
+- Verify
+- Teardown
+
+Note: A test is expected to include these steps in its flow, although
+some may have no content.
+
+--
+
+## Assertion
+
+expected vs actual results 
+
+Note:
+- Appear mainly in the verify step, but may also end up in the setup and
+  teardown.
+- Some test frameworks differentiate the error type when failing in the
+  fixtures or in the test body (exercise and verify step).
+
+--
+
+# Skipping
+
+- Explicitly by the test runner.
+- Explicitly by the test author.
+- Conditioned at run-time.
+
+Note:
+It is useful to:
+- Run a subset of tests, filtering out some.
+- Declare in-code that a test is broken and needs attention (XFail).
+- Dynamically detect that a test cannot run on the platform.
+  I consider this a bad practice, as it may be missed.
+
+Consider the use of marking/labeling to filter the test list.
+This leaves the control to the test runner logic and avoids unintentional
+skips to occur (which in turn introduces holes in the coverage).
+
+--
+
+# Focus
+
+Note:
+This is the opposite of skipping.
+
+Run only a specific test group, which is useful during development.
+
+It emphasises the need to have a test well isolated and not dependent on other
+tests.
+
+---
+
+# Test Best Practices
+
+Note:
+Language and framework agnostic.
+
+May be opinionated and controversial.
+
+<!-- .slide: data-background-image="cat_glasses.jpg" data-background-opacity="0.4"-->
+
+--
+
+# Fail First
+
+Note: Are you sure the test can fail? Maybe it always passes.
+
+--
+
+# Body vs Fixture
+
+Note: Separate setup/teardown from test body
+
+--
+
+<!-- .slide: data-transition="fade" -->
+
+```python
+def test_dog_runs(dog):
+    with Dog("Pingo") as dog:
+        dog.run()
+
+        assert dog.is_running()
+```
+
+--
+
+<!-- .slide: data-transition="fade" -->
+
+```python
+@pytest.fixture
+def dog()
+    with Dog("Pingo") as dog:
+        yield dog
+
+def test_dog_runs(dog):
+    dog.run()
+
+    assert dog.is_running()
+```
+
+--
+
+# Isolation
+
+Note:
+- No dependency between tests.
+- Be a good citizen, clean on exit.
+
+Avoid leaks, it leads to chaos.
+
+--
+
+<!-- .slide: data-transition="fade" -->
+
+```golang
+var _ = Describe("Dog", func() {
+    var dog = &Dog{}
+    Context("is hungry", func() {
+        var gulash := newGulash()
+
+
+        BeforeEach(func() { dog.MakeHungry() })
+
+        It("eats gulash and feels full", func() {
+            dog.Eat(gulash)
+
+            Equal(dog.isHungry()).To(BeFalse())
+        })
+    })
+})
+
+```
+
+--
+
+<!-- .slide: data-transition="fade" -->
+
+```golang
+var _ = Describe("Dog", func() {
+    var dog = &Dog{}
+    Context("is hungry", func() {
+        var gulash := newGulash()
+
+        BeforeEach(func() { dog.Reborn() })
+        BeforeEach(func() { dog.MakeHungry() })
+
+        It("eats gulash and feels full", func() {
+            dog.Eat(gulash)
+
+            Equal(dog.isHungry()).To(BeFalse())
+        })
+    })
+})
+
+```
+
+--
+
+<!-- .slide: data-transition="fade" -->
+
+```golang
+var _ = Describe("Dog", func() {
+    var dog = &Dog{}
+    Context("is hungry", func() {
+        var gulash := newGulash()
+
+        BeforeEach(func() { dog.MakeHungry() })
+        AfterEach(func() { dog.Reborn() })
+
+        It("eats gulash and feels full", func() {
+            dog.Eat(gulash)
+
+            Equal(dog.isHungry()).To(BeFalse())
+        })
+    })
+})
+
+```
+
+--
+
+# Keep Assertions visible
+
+--
+
+# Traceability
+
+--
+
+# Shared Resources
+
+<!-- .slide: data-background-image="share_keyboard.jpg" data-background-opacity="0.3"-->
+
+--
+
+# Continue On Failure
+
+Note: Expect tests to fail, stopping on the first failure is not informative
+      enough.
+      Said that, support leaving the system "freezed" for advance debugging.
+
+<!-- .slide: data-background-image="never_give_up.jpg" data-background-opacity="0.3"-->
+
+--
+
+# Avoid Dead Tests
+
+--
+
+# Parallel Tests
+
+Note: Production code has tests. Tests have only themselves.
+      Do not leave unexecuted code, it rots.
+      Keep only running tests.
+
+<!-- .slide: data-background-image="parallel.jpg" data-background-opacity="0.3"-->
+
+--
+
+# XFail
+
+Expect to Fail
+
+Note:
+Record a detected bug or a missing feature.
+
+--
+
+# !Randomization & Logic
+
+Note:
+Random Testing have their own test category, do not mix them with
+"regular" tests.
+
+Logic in tests should be limited, it competes with production code and
+may by itself be(come) wrong.
+
+---
+
+# The imperfect world 
+
+Workarounds
+
+--
+
+# Stop On Failure
+
+--
+
+# Clean @ Setup
+
+---
+
+# Thank You
+
+https://ehaas.net/slides/decks/go_write_tests_using_pragmatic_best_practices
+

decks/go_write_tests_using_pragmatic_best_practices/content.md

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+		<title>Go Write Tests using Pragmatic Best Practices</title>
+		<meta name="description" content="Tests are written to assure the correctness and quality of the solution they examine.
+Engineers write tests at different stages of the development cycle, starting at unit tests up to e2e tests.
+In fact, for every line of production code, multiple lines of test code is written.
+
+Writing tests is no different from writing production code. In order to keep it running correctly and assist in detecting issues, it needs to be written in a way that can stand the test of time, provide the needed information on failures and be maintained for the project lifetime.
+
+This talk presents test best practices which can be applied at all test stages.
+The practices are focused to help write good tests and provide the needed information for debugging and troubleshooting the issues detected.
+
+While each language and test framework may present different properties and challenges, the practices are agnostic to a specific language/tool.
+
+Examples will be given in Golang using Ginkgo/Gomega and in Python using PyTest.
+
+The talk will cover:
+- Test structure
+- Test isolation
+- Test fixtures vs test body
+- Assertion
+- Traceability
+- Shared resources
+- Dead test (code)
+- Skipping, xfailing or not running
+- Parallel tests
+
+The talk is based on the following blog post: https://ehaas.net/blog/tests-best-practices">
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