Use fully resolvable request paths because we need to be able to refer
to third party modules, and to increase uniformity and explicitness.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
I now let folks override the same target multiple
times inside of `with_overrides` (and then indirectly
inside of `run_test`.)
I may re-impose this restriction in the future, since
most violations are due to code smells, but there are
a few legitimate use cases for this, and the code
can handle it, plus I want to remove some other
ugliness first.
We now just use a module._load hook to inject
stubs into our code.
For conversion purposes I temporarily maintain
the API of rewiremock, apart from the enable/disable
pieces, but I will make a better wrapper in an
upcoming commit.
We can detect when rewiremock is called after
zrequire now, and I fix all the violations in
this commit, mostly by using override.
We can also detect when a mock is needlessly
created, and I fix all the violations in this
commit.
The one minor nuisance that this commit introduces
is that you can only stub out modules in the Zulip
source tree, which is now static/js. This should
not really be a problem--there are usually better
techniques to deal with third party depenencies.
In the prior commit I show a typical workaround,
which is to create a one-line wrapper in your
test code. It's often the case that you can simply
use override(), as well.
In passing I kill off `reset_modules`, and I
eliminated the second argument to zrequire,
which dates back to pre-es6 days.
Move clear_zulip_refs into restore, and rewrite it without lodash. We
no longer need the requires array, and zrequire is now nothing more
than a wrapper around require.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
We can relax this restriction in the future, but
basically every time it came up for me, the test
code was just disorganized, or it had an easy
workaround.
We still need to write to these globals with set_global because the
code being tested reads from them, but the tests themselves should
never need to read from them.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
There is good reason to do this (explanation is bit long!). With the
TypeScript migration, and the require and ES6 migrations that come
with it, we use require instead of set_global which loads the entire
module. Suppose we have a util module, which is used by some other
module, say message_store, and util is being required in message_store
since it is removed from window. Then, if a test zrequires
message_store first, and then zrequires the util module qand mocks one
of its methods, it will not be mocked for the message_store
module. The reason is:
1. zrequire('message_store') leads to require('util').
2. zrequire('util') removes the util module from cache and it is
reloaded. Now the util module in message_store and the one in
the test will be different and any updates to it in tests won't
be reflected in the actual code.
Which can lead to confusion for folks writing tests. I'll mention this
can be avoided doing zrequire('util') first but...that is not ideal.
And, since there was one outlier test that relied on this behavior,
we add the namespace.reset_module function.
ES and TypeScript modules are strict by default and don’t need this
directive. ESLint will remind us to add it to new CommonJS files and
remove it from ES and TypeScript modules.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This just lets us temporarily assign a value
to a field.
Differences with the "override" scheme:
* override only works on globals
* override (when passed in via run_test) will
just automatically clean up at the end of
the function
We want to undo overrides in reverse order,
which is important if you override the
same name more than once in the same
function.
Until today the code basically prevented
us from ever using the original implementation
of a name we stubbed, and most of them start
as undefined due to their parent modules
starting with `set_global`.
But I do want this proper, and I introduced
a tiny pitfall today.
There was only one place where we weren't
overriding a function, and the use case there
was fairly unique.
Knowing that we're dealing with only functions
will simplify override and allow us to add
features like detecting spurious stubs.
This forces us to more explicitly document at the
top of the file what dependencies we are stubbing,
plus it's less magical.
Also, we may want to do occasional audits of
set_global to clean up places where we mock
things like stream_data, which are probably just
easier to use the real version of now that we
have cleaner APIs to set up stream data.
The modules most affected by this change are our
dispatch-oriented tests--basically, all the
modules that test handling of Zulip events
plus hotkey.js.
Before we were making it impossible to reuse
the function again (so we were preventing
leaks), but it's fine to just restore the
original function, especially now that some
of our tests have grown bigger.
Prettier would do this anyway, but it’s separated out for a more
reviewable diff. Generated by ESLint.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Let's say you have module hello.js like so:
// hello.js
const hello_world = i18n.t('Hello world');
exports.get_greeting = () => hello_world;
And then two modules like this:
// apple.js
const hello = require('hello');
exports.foo = () => {
show_greeting(hello.get_greeting());
};
// banana.js
const hello = require('hello');
exports.foo = () => {
display_greeting(hello.get_greeting());
};
The test for apple.js could look like this,
and it won't crash due to the stub:
set_global('i18n', {t: () => {}});
zrequire('hello');
zrequire('apple');
Now let's say your write this broken version
of a test for banana.js:
zrequire('hello');
zrequire('banana');
If you run `./tools/test-js-with-node`, the
"banana" test will pass, because while it
does require "hello", it won't actually
*execute* the code that happens at require
time for "hello", because it's already in
the cache. Here is the code that gets
skipped:
const hello_world = i18n.t('Hello world');
But then if you try to run the banana test
individually, the above line of code will
cause the test to crash. And it will crash
even before you actually try to test the
meaningful code here:
exports.foo = () => {
display_greeting(hello.get_greeting());
};
This commit fixes this leak scenario by just
aggressively clearing out things from the
require cache.
This slows tests down by about 10%, which I think
is worth the extra safety here.
This is not always a behavior-preserving translation: _.extend mutates
its first argument. However, the code does not always appear to have
been written to expect that.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
Anders Kaseorg
Steve Howell
Abhijeet Prasad Bodas
Priyank Patel
Steve Howell
Anders Kaseorg