From 50deaae8720306fc75ee4989114cc292d60d12df Mon Sep 17 00:00:00 2001 From: Paul Duffin Date: Tue, 16 Mar 2021 17:46:12 +0000 Subject: [PATCH] Add OptionalFixturePreparer Sometimes it is necessary to optionally add a preparer. e.g. There are many parameterized tests where one of the parameters is some additional test setup but not every test provides it so it will default to the "zero" value of whatever type is used for the test setup parameter Migrating those tests to use test fixtures will typically require that the test setup parameter be changed to a FixturePreparer, which by default will be nil. Attempting to use a nil FixturePreparer in the test fixtures will fail so the OptionalFixturePreparer was added to wrap a possibly nil FixturePreparer and thereby avoiding complicating each test with similar logic. Bug: 182885307 Test: m nothing Change-Id: Ia12b2af2105fdc69af4e0b909a37a7b86f1af299 --- android/fixture.go | 13 +++++++++++++ android/fixture_test.go | 5 +++-- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/android/fixture.go b/android/fixture.go index 928967d8c..0bff99593 100644 --- a/android/fixture.go +++ b/android/fixture.go @@ -381,6 +381,19 @@ func GroupFixturePreparers(preparers ...FixturePreparer) FixturePreparer { return &compositeFixturePreparer{dedupAndFlattenPreparers(nil, preparers)} } +// NullFixturePreparer is a preparer that does nothing. +var NullFixturePreparer = GroupFixturePreparers() + +// OptionalFixturePreparer will return the supplied preparer if it is non-nil, otherwise it will +// return the NullFixturePreparer +func OptionalFixturePreparer(preparer FixturePreparer) FixturePreparer { + if preparer == nil { + return NullFixturePreparer + } else { + return preparer + } +} + type simpleFixturePreparerVisitor func(preparer *simpleFixturePreparer) // FixturePreparer is an opaque interface that can change a fixture. diff --git a/android/fixture_test.go b/android/fixture_test.go index a31ef1654..0042e5b16 100644 --- a/android/fixture_test.go +++ b/android/fixture_test.go @@ -30,9 +30,10 @@ func TestFixtureDedup(t *testing.T) { preparer1 := appendToList("preparer1") preparer2 := appendToList("preparer2") preparer3 := appendToList("preparer3") - preparer4 := appendToList("preparer4") + preparer4 := OptionalFixturePreparer(appendToList("preparer4")) + nilPreparer := OptionalFixturePreparer(nil) - preparer1Then2 := GroupFixturePreparers(preparer1, preparer2) + preparer1Then2 := GroupFixturePreparers(preparer1, preparer2, nilPreparer) preparer2Then1 := GroupFixturePreparers(preparer2, preparer1)