Expand unit test coverage for the cache layer and realization polling

cache_test.go's tests predated the unittest tag convention and were named
outside the TestMock*Nsxt*/TestUnitNsxt_* pattern that `make test-unit` (and
CI) filters on via -run, so they never actually executed as part of the
tracked unit test suite. Tag the file `//go:build unittest` and rename its
tests to TestUnitNsxt_* so they're finally counted.

Add nsxt/cache_unit_test.go covering the cache.go helpers that were still at
0%: query-string/query-key construction, the per-type/per-query cache
buckets (hit, miss-and-populate, and post-write-bypass paths) including the
composite gateway-policy/security-policy + rule merge, tag stripping and
provider-managed-tag patching, and TryCacheRead/CacheAwareResourceRead/
cacheAwareDataSourceReadByID end to end using the existing cliQueryClient
stub pattern from policy_search_unit_test.go.

Also add coverage for nsxtPolicyWaitForRealizationStateConf (policy_utils.go),
reusing the existing realization-info mock helper to exercise its Refresh
closure (found, not-yet-realized, and error cases).

Package coverage under `go test ./nsxt -tags=unittest -run='^(TestMock.*Nsxt.*|TestUnitNsxt_.*)' -coverpkg=./nsxt`
moves from 74.0% to 74.8%, with cache.go itself going from mostly-0% to
75-100% coverage across nearly every function.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ESMNTML2d2NLax7MHUizHe

Author: 2 people

nsxt/cache_test.go

@@ -1,3 +1,9 @@
+//go:build unittest
+
+// © Broadcom. All Rights Reserved.
+// The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries.
+// SPDX-License-Identifier: MPL-2.0
+
 package nsxt
 
 import (
@@ -10,7 +16,7 @@ import (
 	"github.com/vmware/vsphere-automation-sdk-go/services/nsxt/model"
 )
 
-func TestProviderManagedTagsSearchQuery(t *testing.T) {
+func TestUnitNsxt_providerManagedTagsSearchQuery(t *testing.T) {
 	if got := providerManagedTagsSearchQuery(""); got != "" {
 		t.Fatalf("empty runID: want empty, got %q", got)
 	}
@@ -26,7 +32,7 @@ func TestProviderManagedTagsSearchQuery(t *testing.T) {
 	}
 }
 
-func TestBuildTagQuery(t *testing.T) {
+func TestUnitNsxt_buildTagQuery(t *testing.T) {
 	tagSchema := map[string]*schema.Schema{
 		"tag": {
 			Type:     schema.TypeSet,
@@ -100,7 +106,7 @@ func TestBuildTagQuery(t *testing.T) {
 	})
 }
 
-func TestAttachRulesByParentPathSecurityPolicy(t *testing.T) {
+func TestUnitNsxt_attachRulesByParentPathSecurityPolicy(t *testing.T) {
 	policyPathA := "/infra/domains/default/security-policies/pol-a"
 	policyPathB := "/infra/domains/default/security-policies/pol-b"
 
@@ -138,7 +144,7 @@ func TestAttachRulesByParentPathSecurityPolicy(t *testing.T) {
 	})
 }
 
-func TestEnsureProviderManagedTagsWithPatchFunc(t *testing.T) {
+func TestUnitNsxt_ensureProviderManagedTagsWithPatchFunc(t *testing.T) {
 	type testTagObj struct {
 		Tags []model.Tag
 	}
@@ -217,7 +223,7 @@ func int64Ptr(v int64) *int64 {
 	return &v
 }
 
-func TestGroupRulesByValidParentPath(t *testing.T) {
+func TestUnitNsxt_groupRulesByValidParentPath(t *testing.T) {
 	pathA := "/policies/a"
 	pathB := "/policies/b"
 	valid := map[string]struct{}{pathA: {}, pathB: {}}
@@ -285,7 +291,7 @@ func attachRulesToSecurityPoliciesForTest(parents []model.SecurityPolicy, rules
 	)
 }
 
-func TestAttachRulesByParentPathGatewayPolicy(t *testing.T) {
+func TestUnitNsxt_attachRulesByParentPathGatewayPolicy(t *testing.T) {
 	policyPathA := "/orgs/p/proj/vpcs/vpc/gateway-policies/pol-a"
 	policyPathB := "/orgs/p/proj/vpcs/vpc/gateway-policies/pol-b"
 
@@ -390,7 +396,7 @@ func TestAttachRulesByParentPathGatewayPolicy(t *testing.T) {
 	})
 }
 
-func TestErrCacheUseBackendDirect(t *testing.T) {
+func TestUnitNsxt_errCacheUseBackendDirect(t *testing.T) {
 	if !errors.Is(errCacheUseBackendDirect, errCacheUseBackendDirect) {
 		t.Fatal("errors.Is should match sentinel to itself")
 	}
@@ -400,7 +406,7 @@ func TestErrCacheUseBackendDirect(t *testing.T) {
 	}
 }
 
-func TestReflectStringField(t *testing.T) {
+func TestUnitNsxt_reflectStringField(t *testing.T) {
 	t.Run("returns-pointer-value", func(t *testing.T) {
 		obj := &model.Group{DisplayName: strPtr("g1")}
 		got := reflectStringField(obj, "DisplayName")