diff --git a/lib/trailblazer/test/assertion.rb b/lib/trailblazer/test/assertion.rb
index fb87cce..a8da93f 100644
--- a/lib/trailblazer/test/assertion.rb
+++ b/lib/trailblazer/test/assertion.rb
@@ -56,29 +56,38 @@ def self.actual(asserted, reader, name)
 
       # Assertions for Activity, not for Operation.
       module Activity
-
         def self.invoke_activity(ctx, operation:, **)
           signal, (ctx, _) = operation.call([ctx, {}]) # call with circuit interface. https://trailblazer.to/2.1/docs/operation/#operation-internals-circuit-interface
 
           return signal, ctx
         end
 
-        def self.invoke_activity_with_wtf(ctx, operation:, **)
+        def self.invoke_activity_with_tracing(ctx, operation:, **)
           raise
         end
 
         module Assert
-          def assert_pass(*args, **options, &block)
-            super(*args, **options, invoke: Activity.method(:invoke_activity), &block)
+          def assert_pass(*args, invoke: Activity.method(:invoke_activity), **options, &block)
+            super(*args, **options, invoke: invoke, &block)
+          end
+
+          def assert_fail(*args, invoke: Activity.method(:invoke_activity), **options, &block)
+            super(*args, **options, invoke: invoke, &block)
+          end
+
+# DISCUSS: only for Suite API so far.
+          def assert_pass?(*args, **options, &block)
+            assert_pass(*args, **options, invoke: Activity.method(:invoke_activity_with_tracing), &block)
           end
 
-          def assert_fail(*args, **options, &block)
-            super(*args, **options, invoke: Activity.method(:invoke_activity), &block)
+          def assert_fail?(*args, **options, &block)
+            assert_fail(*args, **options, invoke: Activity.method(:invoke_activity_with_tracing), &block)
           end
+          # TODO: test {#assert_fail?}
         end
 
-        include Assertion # from Test::Assert, top-level
-        include Assert # our assert_* versions.
+        # include Assertion # from Test::Assert, top-level
+        # include Assert # our assert_* versions.
       end
     end
   end
diff --git a/lib/trailblazer/test/assertion/suite.rb b/lib/trailblazer/test/assertion/suite.rb
index 1802931..901a793 100644
--- a/lib/trailblazer/test/assertion/suite.rb
+++ b/lib/trailblazer/test/assertion/suite.rb
@@ -31,11 +31,11 @@ def Ctx(*args, **kws)
         end
 
         def assert_pass?(*args, **kws, &block)
-          assert_pass(*args, **kws, use_wtf: true, &block)
+          assert_pass(*args, **kws, invoke: Assertion::Wtf.method(:invoke_activity), &block)
         end
 
         def assert_fail?(*args, **kws, &block)
-          assert_fail(*args, **kws, use_wtf: true, &block)
+          assert_fail(*args, **kws, invoke: Assertion::Wtf.method(:invoke_activity), &block)
         end
 
         # Provide {Assert.assert_pass} which decouples the assertion logic from the actual test framework.
@@ -87,7 +87,8 @@ def normalize_kws(user_block:, test:, operation: test.operation, expected_attrib
               contract_name:        contract_name,
               model_at:             model_at,
               user_block:           user_block,
-              invoke:               use_wtf ? Assertion::Wtf.method(:invoke_activity) : invoke,
+              # invoke:               use_wtf ? Assertion::Wtf.method(:invoke_activity) : invoke,
+              invoke: invoke,
 
               **normalize_kws_for_ctx(test: test, **options)
             }
diff --git a/test/assertion_test.rb b/test/assertion_test.rb
index e3ec9c9..d54c39d 100644
--- a/test/assertion_test.rb
+++ b/test/assertion_test.rb
@@ -349,7 +349,8 @@ def model(ctx, params:, **)
     end
   end
 
-  include Trailblazer::Test::Assertion::Activity
+  include Trailblazer::Test::Assertion
+  include Trailblazer::Test::Assertion::Activity::Assert
   include Trailblazer::Test::Assertion::AssertExposes
 
   it do
@@ -357,3 +358,30 @@ def model(ctx, params:, **)
       title: "Roxanne"
   end
 end
+
+class AssertionActivitySuiteTest < Minitest::Spec
+  Record = AssertionsTest::Record
+
+  class Create < Trailblazer::Activity::FastTrack
+    step :validate
+    step :model
+
+    def validate(ctx, params:, **)
+      params[:title]
+    end
+
+    def model(ctx, params:, **)
+      ctx[:model] = Record.new(**params)
+    end
+  end
+
+  include Trailblazer::Test::Assertion::Suite
+  include Trailblazer::Test::Assertion::Activity::Assert
+  include Trailblazer::Test::Assertion::AssertExposes
+
+  let(:operation) { Create }
+
+  it do
+    assert_pass?({params: {title: "Roxanne"}}, {title: "Roxanne"})
+  end
+end
diff --git a/test/docs/assertions/pass_fail_test.rb b/test/docs/suite_test.rb
similarity index 100%
rename from test/docs/assertions/pass_fail_test.rb
rename to test/docs/suite_test.rb