Ensure test isolation

Tests should be completely isolated from each other and clean up after themselves to prevent interference.

1. Use testing utilities properly: Leverage the standard library’s testing helpers correctly.

   // GOOD: Let t.TempDir() handle directory creation and cleanup
   td := t.TempDir()
      
   // BAD: Don't call os.MkdirAll() after t.TempDir()
   td := t.TempDir()
   os.MkdirAll(td, 0755) // Unnecessary - directory already exists with proper permissions
   

2. Clean up global state: When tests modify global variables or settings, always restore the original values.

   // GOOD: Save and restore global state
   p := tfversion.Prerelease
   v := tfversion.Version
   defer func() {
     tfversion.Prerelease = p
     tfversion.Version = v
   }()
   

3. Make tests deterministic: Avoid non-deterministic behavior like unsorted maps to prevent flaky tests.

   // GOOD: Sort keys or values before assertion when using maps
   // Instead of directly asserting on map values which may be in random order
   sortedKeys := make([]string, 0, len(someMap))
   for k := range someMap {
     sortedKeys = append(sortedKeys, k)
   }
   sort.Strings(sortedKeys)
   

4. Validate resource cleanup: Tests should verify that all resources are properly cleaned up after running.

   // Verify no resources remain after test
   if provider.ResourceCount() > 0 {
     t.Fatalf("should have deleted all resources on completion but left %v", 
             provider.ResourceString())
   }
   

Properly isolated tests lead to more reliable test suites, easier debugging, and prevent issues where test results depend on execution order.