Address remaining PR test feedback

Root cause: recent test refactors introduced assertion/name mismatches and test-guard synchronization risks that triggered new review threads.

Author: niemyjski

test/Geocoding.Tests/GoogleBusinessKeyTest.cs

@@ -4,6 +4,7 @@
 
 namespace Geocoding.Tests;
 
+[Collection("Settings")]
 public class GoogleBusinessKeyTest
 {
     [Fact]

test/Geocoding.Tests/GoogleGeocoderTest.cs

@@ -184,31 +184,6 @@ public async Task Geocode_WithPostalCodeFilter_ReturnsResultInExpectedPostalCode
         Assert.Contains(addresses, x => HasShortName(x, "94043"));
     }
 
-    [Fact]
-    public void GoogleGeocodingException_WithProviderMessage_PreservesStatusAndMessage()
-    {
-        // Act
-        var exception = new GoogleGeocodingException(GoogleStatus.RequestDenied, "This API is not activated on your API project.");
-
-        // Assert
-        Assert.Equal(GoogleStatus.RequestDenied, exception.Status);
-        Assert.Equal("This API is not activated on your API project.", exception.ProviderMessage);
-        Assert.Contains("RequestDenied", exception.Message);
-        Assert.Contains("This API is not activated on your API project.", exception.Message);
-    }
-
-    [Fact]
-    public void GoogleGeocodingException_WithoutProviderMessage_LeavesProviderMessageNull()
-    {
-        // Act
-        var exception = new GoogleGeocodingException(GoogleStatus.OverQueryLimit);
-
-        // Assert
-        Assert.Equal(GoogleStatus.OverQueryLimit, exception.Status);
-        Assert.Null(exception.ProviderMessage);
-        Assert.Contains("OverQueryLimit", exception.Message);
-    }
-
     [Fact]
     public async Task Geocode_HttpFailure_PreservesInnerExceptionPreview()
     {

test/Geocoding.Tests/GoogleTestGuard.cs

@@ -12,33 +12,54 @@ internal static class GoogleTestGuard
 
     public static void EnsureAvailable(string apiKey)
     {
-        string? skipReason;
+        if (TryGetCachedSkipReason(apiKey, out string? skipReason))
+        {
+            if (!String.IsNullOrWhiteSpace(skipReason))
+                Assert.Skip(skipReason);
+
+            return;
+        }
+
+        string? validatedSkipReason = ValidateCore(apiKey);
 
         lock (_sync)
         {
-            if (_validated && String.Equals(_validatedApiKey, apiKey, StringComparison.Ordinal))
+            if (!_validated || !String.Equals(_validatedApiKey, apiKey, StringComparison.Ordinal))
             {
-                skipReason = _skipReason;
-            }
-            else
-            {
-                skipReason = ValidateCore(apiKey);
                 _validatedApiKey = apiKey;
-                _skipReason = skipReason;
+                _skipReason = validatedSkipReason;
                 _validated = true;
             }
+
+            skipReason = _skipReason;
         }
 
         if (!String.IsNullOrWhiteSpace(skipReason))
             Assert.Skip(skipReason);
     }
 
+    private static bool TryGetCachedSkipReason(string apiKey, out string? skipReason)
+    {
+        lock (_sync)
+        {
+            if (_validated && String.Equals(_validatedApiKey, apiKey, StringComparison.Ordinal))
+            {
+                skipReason = _skipReason;
+                return true;
+            }
+        }
+
+        skipReason = null;
+        return false;
+    }
+
     private static string? ValidateCore(string apiKey)
     {
         try
         {
+            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(20));
             var geocoder = new GoogleGeocoder(apiKey);
-            _ = geocoder.GeocodeAsync("1600 pennsylvania ave nw, washington dc", CancellationToken.None)
+            _ = geocoder.GeocodeAsync("1600 pennsylvania ave nw, washington dc", cts.Token)
                 .GetAwaiter()
                 .GetResult()
                 .FirstOrDefault();
@@ -49,6 +70,10 @@ public static void EnsureAvailable(string apiKey)
         {
             return BuildSkipReason(ex);
         }
+        catch (OperationCanceledException)
+        {
+            return "Google integration test guard timed out while validating API key availability.";
+        }
     }
 
     private static string BuildSkipReason(GoogleGeocodingException ex)

test/Geocoding.Tests/YahooGeocoderTest.cs

@@ -85,7 +85,7 @@ public override Task Geocode_InvalidZipCode_ReturnsResults(string address)
     }
 
     [Fact]
-    public void BuildRequest_GeneratesSignedGetRequest()
+    public void BuildRequest_WithPlacefinderUrl_ReturnsSignedGetRequest()
     {
         // Arrange
         var geocoder = new YahooGeocoder("consumer-key", "consumer-secret");