Clean up all warnings in Java client test

[acarbonetto]

Issue #, if available:

Description of changes:

Cleans up all compiler warnings in the Java/Client/src/test folder. Most of the changes are like this:

        CompletableFuture<Object> testResponse = mock(CompletableFuture.class);
        when(testResponse.get()).thenReturn(value);

changed to:

        CompletableFuture<Object> testResponse = new CompletableFuture<>();
        testResponse.complete(value);

The above tests clean up the type error when converting from CompletableFuture to CompletableFuture<Object>.

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[Yury-Fridlyand]

There are few more unchecked casts in RedisClusterClientTest and in FfiTest
Try adding

tasks.withType(JavaCompile) {
    options.compilerArgs << '-Xlint:unchecked'
    options.deprecation = true
}

to build.gradle and rerun ./gradlew compileTest

[Yury-Fridlyand]

Please add @Timeout for client UTs

[acarbonetto]

Please add @Timeout for client UTs

It's just ConnectionWithGlideMockTests.java. Do we need it for that test?

[Yury-Fridlyand]

I hanged once UTs by using incorrect mockito's mock.

[Yury-Fridlyand]

There are 2 UTs which still mocking a future:

• type_returns_success
• time_returns_success

[barshaul]

Please send a ping once CI is passing

[Yury-Fridlyand]

@barshaul

[barshaul]

why? what's the warning? can't it be fixed other way?

[Yury-Fridlyand]

Supplier is a paramtrized type (it has <>), but mock returns a raw type of Supplier and can't return Supplier<something>.
Assigning Supplier to a Supplier<...> does not require a cast, but it produces a compiler warning, which we acknoledge and suppress.
If we keep using raw Supplier we have another warning about using raw types, which should be also suppressed.

[acarbonetto]

We can use an actual supplier instead of mocks. We would lose the verify check, but that's not really important.

[barshaul]

same qustion

[Yury-Fridlyand]

I updated code here and change suppression to be the same as above.
Meanwhile, a good read https://stackoverflow.com/a/9542131/21176342

[barshaul]

Please explain the SuppressWarnings, other than that looks ok.