diff --git a/test/CodoMetis.TypeKit.Analyzers.Tests/AnalyzerTest.cs b/test/CodoMetis.TypeKit.Analyzers.Tests/AnalyzerTest.cs
index 061fe50..9e98fad 100644
--- a/test/CodoMetis.TypeKit.Analyzers.Tests/AnalyzerTest.cs
+++ b/test/CodoMetis.TypeKit.Analyzers.Tests/AnalyzerTest.cs
@@ -31,6 +31,20 @@ public AnalyzerTest(string source, bool referenceTypeKit = true)
     }
 }
 
+/// <summary>What a sweep over a variant catalogue leaves to the focused tests of its rule.</summary>
+/// <remarks>
+/// The verifier runs a case that expects a diagnostic a second time, under <c>#pragma warning disable</c> for each id
+/// it expects, and checks that nothing is left. Whether a pragma silences a rule is the compiler's, the same for every
+/// shape, so a sweep paid for that pass once per row: 28% of DroppedTaskVariantTests' time (#245). The focused tests
+/// of each rule keep it. The verifier's other pass, under an <c>&lt;auto-generated&gt;</c> header, never runs here:
+/// every analyzer configures generated-code analysis (<c>GeneratedCode.AnalysisFlags</c>), and GeneratedCodeTests
+/// holds what each rule does in generated code.
+/// </remarks>
+internal static class VariantSweep
+{
+    public const TestBehaviors Behaviors = TestBehaviors.SkipSuppressionCheck;
+}
+
 /// <summary>A verifier run of one analyzer and its code fix: the source, then the source as the fix leaves it.</summary>
 internal sealed class CodeFixTest<TAnalyzer, TCodeFix> : CSharpCodeFixTest<TAnalyzer, TCodeFix, DefaultVerifier>
     where TAnalyzer : DiagnosticAnalyzer, new()
diff --git a/test/CodoMetis.TypeKit.Analyzers.Tests/CodoMetis.TypeKit.Analyzers.Tests.csproj b/test/CodoMetis.TypeKit.Analyzers.Tests/CodoMetis.TypeKit.Analyzers.Tests.csproj
index a6513c1..e287115 100644
--- a/test/CodoMetis.TypeKit.Analyzers.Tests/CodoMetis.TypeKit.Analyzers.Tests.csproj
+++ b/test/CodoMetis.TypeKit.Analyzers.Tests/CodoMetis.TypeKit.Analyzers.Tests.csproj
@@ -23,4 +23,15 @@
         <PackageReference Include="System.Security.Cryptography.Pkcs" />
     </ItemGroup>
 
+    <!--
+      parallelMode "all": every row of a theory runs in parallel, not only the test classes (xunit.v3 4.x). Each
+      variant sweep is one class of hundreds to thousands of rows, which the default mode ran one after another:
+      DroppedTaskVariantTests alone kept CI's test step going for two to seven minutes after every other test
+      project had finished (#245). Every test here builds its own compilation and shares nothing with another, so
+      none opts out.
+    -->
+    <ItemGroup>
+        <None Update="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
+    </ItemGroup>
+
 </Project>
diff --git a/test/CodoMetis.TypeKit.Analyzers.Tests/DroppedTaskVariantTests.cs b/test/CodoMetis.TypeKit.Analyzers.Tests/DroppedTaskVariantTests.cs
index 4f3544e..34b80ff 100644
--- a/test/CodoMetis.TypeKit.Analyzers.Tests/DroppedTaskVariantTests.cs
+++ b/test/CodoMetis.TypeKit.Analyzers.Tests/DroppedTaskVariantTests.cs
@@ -36,6 +36,7 @@ public Task A_dropped_task_is_reported_in_every_form_and_a_kept_one_never(string
         var (source, expected) = DroppedTaskShapes.Use(call, form);
 
         var test = new AnalyzerTest<IgnoredOutcomeAnalyzer>(source);
+        test.TestBehaviors = VariantSweep.Behaviors;
         test.TestState.Sources.Add(("Declarations.cs", DroppedTaskShapes.Declarations));
         test.TestState.AdditionalReferences.Add(RealTesting.Reference);
         test.ExpectedDiagnostics.AddRange(
diff --git a/test/CodoMetis.TypeKit.Analyzers.Tests/QueryDelegateConditionTests.cs b/test/CodoMetis.TypeKit.Analyzers.Tests/QueryDelegateConditionTests.cs
index c0f84da..550e59e 100644
--- a/test/CodoMetis.TypeKit.Analyzers.Tests/QueryDelegateConditionTests.cs
+++ b/test/CodoMetis.TypeKit.Analyzers.Tests/QueryDelegateConditionTests.cs
@@ -133,6 +133,7 @@ private static Task Sweep(QueryReceiver receiver, string element, string paramet
         var (source, expected) = QueryDelegateShapes.Use(receiver, element, parameters, where);
 
         var test = new AnalyzerTest<DefaultProducingCallAnalyzer>(TypeArgumentKinds.Candidates);
+        test.TestBehaviors = VariantSweep.Behaviors;
         test.TestState.Sources.Add(("Declarations.cs", QueryDelegateShapes.Declarations));
         test.TestState.Sources.Add(("Use.cs", source));
         test.ExpectedDiagnostics.AddRange(expected.Select(call => new DiagnosticResult("CMTK0009", DiagnosticSeverity.Warning).WithLocation(call.Location)));
diff --git a/test/CodoMetis.TypeKit.Analyzers.Tests/TypeArgumentConstraintKindTests.cs b/test/CodoMetis.TypeKit.Analyzers.Tests/TypeArgumentConstraintKindTests.cs
index b295217..7b28e0e 100644
--- a/test/CodoMetis.TypeKit.Analyzers.Tests/TypeArgumentConstraintKindTests.cs
+++ b/test/CodoMetis.TypeKit.Analyzers.Tests/TypeArgumentConstraintKindTests.cs
@@ -215,6 +215,7 @@ public void The_catalogue_names_are_unique_and_its_pairs_reach_every_verdict()
     private static Task Run(string subject, string use, bool breaking)
     {
         var test = new AnalyzerTest<TypeArgumentConstraintAnalyzer>(TypeArgumentKinds.Candidates + subject);
+        test.TestBehaviors = VariantSweep.Behaviors;
         test.TestState.Sources.Add(("Use.cs", use));
 
         if (breaking)
diff --git a/test/CodoMetis.TypeKit.Analyzers.Tests/Variants/TypeArgumentSiteRun.cs b/test/CodoMetis.TypeKit.Analyzers.Tests/Variants/TypeArgumentSiteRun.cs
index ca86c37..bf2c7bb 100644
--- a/test/CodoMetis.TypeKit.Analyzers.Tests/Variants/TypeArgumentSiteRun.cs
+++ b/test/CodoMetis.TypeKit.Analyzers.Tests/Variants/TypeArgumentSiteRun.cs
@@ -40,6 +40,7 @@ public static Task Verify<TAnalyzer>(TypeArgumentSubject subject, string siteNam
         var use       = Fill(site.Use, subject, argument);
 
         var test = new AnalyzerTest<TAnalyzer>(Fill(TypeArgumentSites.Subjects + subject.Declarations, subject, argument));
+        test.TestBehaviors = VariantSweep.Behaviors;
         test.TestState.Sources.Add((site.File, reported ? use : Unmarked(use)));
 
         if (reported)
diff --git a/test/CodoMetis.TypeKit.Analyzers.Tests/xunit.runner.json b/test/CodoMetis.TypeKit.Analyzers.Tests/xunit.runner.json
new file mode 100644
index 0000000..82eb3ce
--- /dev/null
+++ b/test/CodoMetis.TypeKit.Analyzers.Tests/xunit.runner.json
@@ -0,0 +1,4 @@
+{
+  "$schema": "https://xunit.net/schema/v3/xunit.runner.schema.json",
+  "parallelMode": "all"
+}