Implementing a test suite was impossible outside of the
k8s.io/kubernetes/test/e2e/storage/testsuites package because all
interfaces and structs used by them were private.
As part of revamping the API, genericVolumeTestResource also gets
exported because it is useful for other test suites. Because the
TestResource interface became obsolete a while ago and isn't used
anymore, the new name is just testsuites.VolumeResource.
testpatterns.CSIInlineVolume needs special handling in a few places.
It can now be used in a test pattern for a test suite that uses a
VolumeResource instance.
CreateDriver (now called SetupTest) is a potentially expensive
operation, depending on the driver. Creating and tearing down a
framework instance also takes time (measured at 6 seconds on a fast
machine) and produces quite a bit of log output.
Both can be avoided for tests that skip based on static
information (like for instance the current OS, vendor, driver and test
pattern) by making the test suite responsible for creating framework
and driver.
The lifecycle of the TestConfig instance was confusing because it was
stored inside the DriverInfo, a struct which conceptually is static,
while the TestConfig is dynamic. It is cleaner to separate the two,
even if that means that an additional pointer must be passed into some
functions. Now CreateDriver is responsible for initializing the
PerTestConfig that is to be used by the test.
To make this approach simpler to implement (= less functions which
need the pointer) and the tests easier to read, the entire setup and
test definition is now contained in a single function. This is how it
is normally done in Ginkgo. This is easier to read because one can see
at a glance where variables are set, instead of having to trace values
though two additional structs (TestResource and TestInput).
Because we are changing the API already, also other changes are made:
- some function prototypes get simplified
- the naming of functions is changed to match their purpose
(tests aren't executed by the test suite, they only get defined
for later execution)
- unused methods get removed (TestSuite.skipUnsupportedTest is redundant)
This increases type safety and makes the code easier to read because
it becomes obvious that the "test resource" passed to some functions
must be the result of a previous CreateVolume.
This makes it possible to remove:
- functions that never did anything (the DeleteVolume methods in
drivers that never create a volume)
- type casts (in the DeleteVolume implementation)
- the unused DeleteVolume parameters
- the stand-alone DeleteVolume function (which would be just a non-nil
check)
GetPersistentVolumeSource and GetVolumeSource could also become
methods on more specific interfaces - they don't actually use anything
from TestDriver instance which provides them.
The main motivation however is to reduce the number of methods which
might need an explicit test config parameter.
Exposing framework.VolumeTestConfig as part of the testsuite package
API was confusing because it was unclear which of the values in it
really have an effect. How it was set also was a bit awkward: a test
driver had a copy that had to be overwritten at test runtime and then
might have been updated and/or overwritten again by the driver.
Now testsuites has its own test config structure. It contains the
values that might have to be set dynamically at runtime. Instead of
overwriting a copy of that struct inside the test driver, the test
driver takes some common defaults (specifically, the framework pointer
and the prefix) when it gets initialized and then manages its own
copy. For example, the hostpath driver has to lock the pods to a
single node.
framework.VolumeTestConfig is still used internally and test drivers
can decide to run tests with a fully populated instance if needed (for
example, after setting up an NFS server).
This makes it possible to use the testsuites package out-of-tree
without pulling in unnecessary dependencies and code (in
test/e2e/storage/vsphere) that defines tests that are not wanted in a
custom test suite.
