Enhance test isolation by adding copy constructors and ensuring fresh instances of BrowserVersion across tests (#410)

Author: thomhurst

Saucery.Core/DataSources/SauceryTestData.cs

@@ -24,20 +24,31 @@ private static void ExpandAndFilter(List<SaucePlatform> platforms, PlatformConfi
         BrowserVersions = platformConfigurator.FilterAll(expandedPlatforms);
     }
 
-    public static IEnumerable<BrowserVersion> Items => 
+    /// <summary>
+    /// Returns fresh instances to ensure test isolation.
+    /// Each access creates new BrowserVersion instances to prevent state leakage across tests.
+    /// </summary>
+    public static IEnumerable<BrowserVersion> Items =>
         BrowserVersions!
-            .Select(x => x)
+            .Select(x => new BrowserVersion(x))
             .AsEnumerable();
 
+    /// <summary>
+    /// Returns platforms wrapped in object arrays, with fresh instances for test isolation.
+    /// </summary>
     protected static IEnumerable<object[]> GetAllPlatforms() {
         List<object[]> allPlatforms = [];
         allPlatforms.AddRange(Items.Select(platform => (object[])[platform]));
 
         return allPlatforms.AsEnumerable();
     }
 
+    /// <summary>
+    /// Returns factory functions that create fresh BrowserVersion instances when invoked.
+    /// This ensures each test gets its own independent instance, preventing state leakage.
+    /// </summary>
     protected static List<Func<BrowserVersion>> GetAllPlatformsAsFunc() =>
-        [.. Items.Select(platform => (Func<BrowserVersion>)(() => platform))];
+        [.. BrowserVersions!.Select(template => (Func<BrowserVersion>)(() => new BrowserVersion(template)))];
 }
 /*
 * Copyright Andrew Gray, SauceForge

Saucery.Core/Dojo/BrowserVersion.cs

@@ -84,6 +84,26 @@ public BrowserVersion(SaucePlatform platform) {
         ScreenResolutions = [];
     }
 
+    /// <summary>
+    /// Copy constructor - creates a new independent instance with the same values.
+    /// This ensures test isolation by preventing shared mutable state.
+    /// </summary>
+    public BrowserVersion(BrowserVersion other) {
+        Os = other.Os;
+        PlatformNameForOption = other.PlatformNameForOption;
+        BrowserName = other.BrowserName;
+        Name = other.Name;
+        AutomationBackend = other.AutomationBackend;
+        DeviceName = other.DeviceName;
+        RecommendedAppiumVersion = other.RecommendedAppiumVersion;
+        SupportedBackendVersions = [..other.SupportedBackendVersions];
+        DeprecatedBackendVersions = [..other.DeprecatedBackendVersions];
+        DeviceOrientation = other.DeviceOrientation;
+        ScreenResolution = other.ScreenResolution;
+        PlatformType = other.PlatformType;
+        ScreenResolutions = [..other.ScreenResolutions];
+    }
+
     /// <summary>
     /// Generates a unique test name from this configuration and the test context.
     /// This does not mutate the BrowserVersion instance.

Saucery.Core/Dojo/DojoExtensions.cs

@@ -122,7 +122,7 @@ public static IList<T> GetPlatform<T>(this List<PlatformBase> availablePlatforms
             b.Os.Equals(sp.Os, StringComparison.Ordinal) &&
             b.Name.Equals(sp.Browser, StringComparison.OrdinalIgnoreCase));
 
-        return sp.ScreenResolution == string.Empty
+        var template = sp.ScreenResolution == string.Empty
             ? browser?.BrowserVersions.FirstOrDefault(v =>
                 v.Os.Equals(sp.Os, StringComparison.Ordinal) &&
                 v.BrowserName.Equals(sp.Browser, StringComparison.OrdinalIgnoreCase) &&
@@ -132,6 +132,9 @@ public static IList<T> GetPlatform<T>(this List<PlatformBase> availablePlatforms
                 v.BrowserName.Equals(sp.Browser, StringComparison.OrdinalIgnoreCase) &&
                 v.Name!.Equals(sp.BrowserVersion, StringComparison.OrdinalIgnoreCase) &&
                 v.ScreenResolutions.Contains(sp.ScreenResolution));
+
+        // Return a new instance instead of a reference to prevent state leakage across tests
+        return template != null ? new BrowserVersion(template) : null;
     }
 
     public static BrowserVersion? FindAndroidBrowser(this List<PlatformBase> platforms, SaucePlatform sp)
@@ -160,12 +163,15 @@ public static IList<T> GetPlatform<T>(this List<PlatformBase> availablePlatforms
             b.Os.Equals(sp.Os, StringComparison.Ordinal) &&
             b.DeviceName.Equals(sp.LongName, StringComparison.Ordinal));
 
-        return browser?.BrowserVersions.Count == 1
+        var template = browser?.BrowserVersions.Count == 1
             ? browser.BrowserVersions[0]
             : browser?.BrowserVersions.FirstOrDefault(v =>
                 v.Os.Equals(sp.Os, StringComparison.Ordinal) &&
                 v.DeviceName.Equals(sp.LongName, StringComparison.Ordinal) &&
                 v.Name!.Equals(sp.BrowserVersion, StringComparison.Ordinal));
+
+        // Return a new instance instead of a reference to prevent state leakage across tests
+        return template != null ? new BrowserVersion(template) : null;
     }
 
     public static PlatformBase? FindAndroidPlatform(this List<PlatformBase> platforms, SaucePlatform sp)
@@ -212,12 +218,15 @@ public static IList<T> GetPlatform<T>(this List<PlatformBase> availablePlatforms
             b.PlatformNameForOption.Equals(sp.Os, StringComparison.Ordinal) &&
             b.DeviceName.Equals(sp.LongName, StringComparison.Ordinal));
 
-        return browser?.BrowserVersions.Count == 1
+        var template = browser?.BrowserVersions.Count == 1
             ? browser.BrowserVersions[0]
             : browser?.BrowserVersions.FirstOrDefault(v =>
                 v.PlatformNameForOption.Equals(sp.Os, StringComparison.Ordinal) &&
                 v.DeviceName.Equals(sp.LongName, StringComparison.Ordinal) &&
                 v.Name!.Equals(sp.BrowserVersion, StringComparison.Ordinal));
+
+        // Return a new instance instead of a reference to prevent state leakage across tests
+        return template != null ? new BrowserVersion(template) : null;
     }
 
     public static PlatformBase? FindIOSPlatform(this List<PlatformBase> platforms, SaucePlatform sp)