Add comprehensive unit tests for cache policy mapping

[AnthonyMDev]

Summary

This PR adds comprehensive unit tests for the cache policy conversion functionality added in #859, which maps Apollo's FetchBehavior to URLRequest.CachePolicy.

Changes

• New test file: GraphQLRequestCachePolicyTests.swift with 18 test cases covering:

  • All 5 standard cache policies (CacheOnly, CacheAndNetwork, CacheFirst, NetworkFirst, NetworkOnly)
  • 4 undefined/edge case FetchBehavior combinations
  • Different operation types (queries, mutations, subscriptions)
  • Cache policy persistence across request modifications
  • URL cache behavior verification

• Minor API change: Changed FetchBehavior.init from fileprivate to internal to enable testing custom combinations while keeping it internal to the package

Test Coverage

✅ All 18 tests pass successfully

Tests verify that:

• Each standard FetchBehavior maps to the correct URLRequest.CachePolicy
• Undefined combinations safely fallback to .reloadIgnoringLocalCacheData
• Cache policy is correctly set for all operation types
• Cache policy persists correctly when modifying requests
• URL cache doesn't interfere with Apollo's cache strategy

Test Results

** TEST SUCCEEDED **

Related to #859

🤖 Generated with Claude Code

Co-Authored-By: Claude noreply@anthropic.com

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Build ID: 190fff59bb9ebee60247c549
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[calvincestari]

Looks like there are some duplicate tests, or am I missing the differences?

[calvincestari]

Isn't this test the same as test__cachePolicy__givenCacheOnly__shouldReturnCacheDataDontLoad?

[calvincestari]

The next two tests also appear to be duplicates of test__cachePolicy__givenCacheAndNetwork__shouldReloadIgnoringLocalCache and test__cachePolicy__givenNetworkOnly__shouldReloadIgnoringLocalCache respectively.