Fix expected body when using generators

lib/pact/provider/request.rb

@@ -29,7 +29,7 @@ def body
           when String then expected_request.body
           when NullExpectation then ''
           else
-            Pact::Generators.apply_generators(expected_request, "body", reified_body, @state_params)
+            generated_body
           end
         end
 
@@ -60,6 +60,19 @@ def reified_body
           end
         end
 
+        def generated_body
+          result = Pact::Provider::Generators.apply_generators(expected_request, "body", reified_body, @state_params)
+
+          case result
+          when Hash
+            result.to_json
+          when String
+            result
+          else
+            raise "Expected body to be a String or Hash, but was #{result.class} with value #{result.inspect}"
+          end
+        end
+
         def rack_request_header_for header
           with_http_prefix(header.to_s.upcase).tr('-', '_')
         end

spec/lib/pact/provider/request_spec.rb

@@ -6,13 +6,15 @@
   let(:path) { '/path?something' }
   let(:body) { { a: 'body' } }
   let(:headers) { {} }
+  let(:generators) { {} }
   let(:expected_request) do
     instance_double(
       'Pact::Request::Expected',
       method: 'post',
       full_path: path,
       body: body,
-      headers: headers
+      headers: headers,
+      generators: generators,
     )
   end
 
@@ -69,6 +71,15 @@
       it "returns the object as a json string" do
         expect(subject.body).to eq body.to_json
       end
+
+      context "and it uses generators" do
+        let(:body) { { a: 'body', b: '2025-04-08' } }
+        let(:generators) { {"body"=>{"b"=>{"type"=>"Date"}}} }
+
+        it "returns the object as a json string" do
+          expect(subject.body).to eq body.to_json
+        end
+      end
     end
   end
 
@@ -127,4 +138,4 @@
       end
     end
   end
-end
+end