Test OracleService

[Hecate2]

Description

Adding tests

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[Hecate2]

For now the new test just "seems" to pass.
At https://github.com/Hecate2/neo/blob/4f4f2ccfafb2d57cb310dd025771715e442c7b6f/tests/Neo.Plugins.OracleService.Tests/E2E_Https.cs#L98
After we call s_oracle.Start, we cannot pass the CheckOracleAvailable at https://github.com/Hecate2/neo/blob/fbb607b31f54921569e71c4abbe764eb6f096240/src/Plugins/OracleService/OracleService.cs#L136 . But in RoleManagement.cs, we do have identical keys built from GetDesignatedByRole and DesignateAsRole (both keys are 248 255 255 255 8 0 0 0 2).
I am still wondering why.

[Hecate2]

Now it hits

neo/src/Plugins/OracleService/Protocols/OracleHttpsProtocol.cs

Line 65 in c69791f

message = await client.GetAsync(uri, HttpCompletionOption.ResponseContentRead, cancellation);

but never goes to the next line. No exception was thrown (cancellation token timeout has been considered). This may be because the async tasks are never awaited.