[Internal] Tests: Refactor GatewayTests to use async/await instead of sync-over-async

[kirankumarkolli]

Summary

GatewayTests.cs contains 81 sync-over-async anti-patterns (~60 .Result, ~10 .Wait()) — the largest offender in the test suite. These should be converted to proper async/await.

File

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/GatewayTests.cs

What to fix

Key methods (16 identified):

• ValidateStoredProceduresInternal: void, 24 sync calls — convert to async Task
• ValidateTriggersInternal: already async Task, 11 .Result calls — replace with await
• ValidatePOCODocumentSerialization: already async Task, 7 .Result calls
• ValidateStoredProcedureCrudAsync: already async Task, 4 .Result calls
• ValidateStoredProceduresBlacklistingInternal: already async Task, 3 sync calls
• ValidateUserDefinedFunctions: already async Task, 4 .Result calls
• ValidateStoredProcedureExecutionWithPartitionKey: already async Task, 3 .Result calls
• ValidateTriggersNameBased: void, 4 sync calls
• ValidateUserDefinedFunctionTimeout: void, 2 .Result calls
• Plus ~7 more helper methods with 1-4 sync calls each

Fix approach

1. For methods already marked async Task but containing .Result or .Wait(): replace with await
2. For void methods: convert to async Task, replace .Result with await, .Wait() with await
3. Fix any AggregateException catch blocks to catch the unwrapped exception type
4. When converting helpers to async, update ALL callers

Patterns

• someAsyncCall().Result → await someAsyncCall()
• someAsyncCall().Result.Property → (await someAsyncCall()).Property
• someAsyncCall().Wait() → await someAsyncCall()
• public void TestMethod() → public async Task TestMethod()
• catch (AggregateException ex) { ... ex.InnerException ... } → catch (SpecificException)

Branch naming

Use users/copilot/fix-sync-over-async-gatewaytests

PR title format

[Internal] Tests: Refactors GatewayTests to use async/await instead of sync-over-async

Notes

• This is a LARGE file — be methodical, search for ALL .Result and .Wait() occurrences
• Some methods have BOTH proper await calls AND .Result calls — fix only the .Result calls
• Do NOT modify SynchronizationContextTests.cs
• Build verification: dotnet build Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.EmulatorTests/Microsoft.Azure.Cosmos.EmulatorTests.csproj --no-restore -c Debug
• Related PRs: [Internal] Tests: Refactors StoreReaderTest to use async/await instead of sync-over-async #5766 (StoreReaderTest), [Internal] Tests: Refactors GlobalDatabaseAccountTests to use async/await instead of sync-over-async #5767 (GlobalDatabaseAccountTests)

[kirankumarkolli]

Closing already fixed in PR #5775.