diff --git a/types/invoker.go b/types/invoker.go
index 1170972..5bcd233 100644
--- a/types/invoker.go
+++ b/types/invoker.go
@@ -15,45 +15,67 @@ type Invoker struct {
 	GatewayURL    string
 }
 
-func (i *Invoker) Invoke(topicMap *TopicMap, topic string, message *[]byte) {
-	if len(*message) > 0 {
+type InvocationResult struct {
+	StatusCode int
+	Body       *[]byte
+	Error      error
+}
 
-		matchedFunctions := topicMap.Match(topic)
-		for _, matchedFunction := range matchedFunctions {
+func NewInvocationResult(statusCode int, body *[]byte, error error) *InvocationResult {
+	return &InvocationResult{StatusCode: statusCode, Body: body, Error: error}
+}
 
-			log.Printf("Invoke function: %s", matchedFunction)
+type InvocationResponse struct {
+	StatusCode int
+	Body       *[]byte
+	Headers http.Header
+}
 
-			gwURL := fmt.Sprintf("%s/function/%s", i.GatewayURL, matchedFunction)
-			reader := bytes.NewReader(*message)
+func NewInvocationResponse(statusCode int, body *[]byte, headers http.Header) *InvocationResponse {
+	return &InvocationResponse{StatusCode: statusCode, Body: body, Headers: headers}
+}
 
-			body, statusCode, doErr := invokefunction(i.Client, gwURL, reader)
+func (i *Invoker) Invoke(topicMap *TopicMap, topic string, message *[]byte) (result map[string]*InvocationResult) {
+	result = make(map[string]*InvocationResult)
 
-			if doErr != nil {
-				log.Printf("Unable to invoke from %s, error: %s\n", matchedFunction, doErr)
-				return
-			}
+	if message != nil && len(*message) > 0 {
 
-			printBody := false
-			stringOutput := ""
+		matchedFunctions := topicMap.Match(topic)
+		for _, matchedFunction := range matchedFunctions {
 
-			if body != nil && i.PrintResponse {
-				stringOutput = string(*body)
-				printBody = true
-			}
+			log.Printf("Invoke function: %s", matchedFunction)
+			functionURL := fmt.Sprintf("%s/function/%s", i.GatewayURL, matchedFunction)
+			reader := bytes.NewReader(*message)
 
-			if printBody {
-				log.Printf("Response [%d] from %s %s", statusCode, matchedFunction, stringOutput)
+			response, err := i.performInvocation(functionURL, reader)
 
+			if err != nil {
+				if response != nil {
+					result[matchedFunction] = NewInvocationResult(response.StatusCode, nil, err)
+				} else {
+					result[matchedFunction] = NewInvocationResult(-1, nil, err)
+				}
 			} else {
-				log.Printf("Response [%d] from %s", statusCode, matchedFunction)
+				result[matchedFunction] = NewInvocationResult(response.StatusCode, response.Body, err)
+			}
+
+			if response != nil && response.Body != nil && i.PrintResponse {
+				stringOutput := string(*response.Body)
+				log.Printf("Headers: %s", response.Headers)
+				log.Printf("Response: [%d] from %s %s", response.StatusCode, matchedFunction, stringOutput)
 			}
 		}
 	}
+	return result
 }
 
-func invokefunction(c *http.Client, gwURL string, reader io.Reader) (*[]byte, int, error) {
+func (i *Invoker) performInvocation(functionURL string, bodyReader io.Reader) (*InvocationResponse, error) {
 
-	httpReq, _ := http.NewRequest(http.MethodPost, gwURL, reader)
+	httpReq, requestErr := http.NewRequest(http.MethodPost, functionURL, bodyReader)
+
+	if requestErr != nil {
+		return nil, requestErr
+	}
 
 	if httpReq.Body != nil {
 		defer httpReq.Body.Close()
@@ -61,9 +83,9 @@ func invokefunction(c *http.Client, gwURL string, reader io.Reader) (*[]byte, in
 
 	var body *[]byte
 
-	res, doErr := c.Do(httpReq)
+	res, doErr := i.Client.Do(httpReq)
 	if doErr != nil {
-		return nil, http.StatusServiceUnavailable, doErr
+		return nil, doErr
 	}
 
 	if res.Body != nil {
@@ -72,11 +94,11 @@ func invokefunction(c *http.Client, gwURL string, reader io.Reader) (*[]byte, in
 		bytesOut, readErr := ioutil.ReadAll(res.Body)
 		if readErr != nil {
 			log.Printf("Error reading body")
-			return nil, http.StatusServiceUnavailable, doErr
+			return NewInvocationResponse(res.StatusCode, nil, res.Header), readErr
 
 		}
 		body = &bytesOut
 	}
 
-	return body, res.StatusCode, doErr
+	return NewInvocationResponse(res.StatusCode, body, res.Header), nil
 }
diff --git a/types/invoker_test.go b/types/invoker_test.go
new file mode 100644
index 0000000..8862852
--- /dev/null
+++ b/types/invoker_test.go
@@ -0,0 +1,147 @@
+// Copyright (c) OpenFaaS Project 2018. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+package types
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestInvoker_Invoke(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		function := strings.Split(r.URL.Path, "/")[2]
+
+		switch function {
+		case "success":
+			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(200)
+			w.Write([]byte("Hello World"))
+			break
+		case "headers":
+			w.Header().Set("Access-Control-Allow-Origin", "*")
+			w.Header().Set("Content-Type", "text/html")
+			w.Header().Set("Charset", "utf-8")
+			w.WriteHeader(200)
+			w.Write([]byte("<h1>Hello World</h1>"))
+			break
+		case "wrong_payload":
+			w.WriteHeader(400)
+			w.Write([]byte(""))
+			break
+		case "aborts":
+			if wr, ok := w.(http.Hijacker); ok {
+				conn, _, err := wr.Hijack()
+				if err != nil{
+					fmt.Printf("Recieved %s",err)
+				}else{
+					conn.Close()
+				}
+
+			}
+			break
+		case "server_error":
+			w.WriteHeader(500)
+			w.Write([]byte(""))
+			break
+		}
+	}))
+
+	client := srv.Client()
+	topicMap := NewTopicMap()
+
+	sampleFunc := map[string][]string{
+		"All":        []string{"success", "headers", "wrong_payload"},
+		"Contains_Fail":   []string{"success", "server_error", "aborts", "headers"},
+		"NOP": []string{},
+	}
+
+	topicMap.Sync(&sampleFunc)
+
+	t.Run("Should invoke no function when body is nil", func(t *testing.T) {
+		target := &Invoker{
+			PrintResponse:false,
+			Client:client,
+			GatewayURL: srv.URL,
+		}
+
+		results := target.Invoke(&topicMap, "NOP", nil)
+
+		if len(results) != 0 {
+			t.Errorf("When body is nil it should perform a request")
+		}
+	})
+
+	t.Run("Should invoke no function when body is empty", func(t *testing.T) {
+		target := &Invoker{
+			true,
+			client,
+			srv.URL,
+		}
+
+		body := []byte("")
+		results := target.Invoke(&topicMap, "NOP", &body)
+
+		if len(results) != 0 {
+			t.Errorf("When body is empty it should perform a request")
+		}
+	})
+
+	t.Run("Should invoke all functions", func(t *testing.T) {
+		target := &Invoker{
+			true,
+			client,
+			srv.URL,
+		}
+
+		body := []byte("Some Input")
+		results := target.Invoke(&topicMap, "All", &body)
+
+		const ExpectedResults = 3
+		if len(results) != ExpectedResults {
+			t.Errorf("Expected %d results recieved %d", ExpectedResults, len(results))
+		}
+
+		for name, result := range results {
+			if result.Error != nil {
+				t.Errorf("Received unexpected error %s for %s", result.Error, name)
+			}
+
+			if result.StatusCode != 200 && result.StatusCode != 400 {
+				t.Errorf("Received unexpected status code %d for %s", result.StatusCode, name)
+			}
+		}
+
+	})
+
+	t.Run("Should invoke all functions even if one request fails", func(t *testing.T) {
+		target := &Invoker{
+			true,
+			client,
+			srv.URL,
+		}
+
+		body := []byte("Hello World")
+		results := target.Invoke(&topicMap, "Contains_Fail", &body)
+
+		const ExpectedResults = 4
+		if len(results) != ExpectedResults {
+			t.Errorf("Expected %d results recieved %d", ExpectedResults, len(results))
+		}
+
+		for name, result := range results {
+			if name == "aborts" {
+				if result.Error == nil {
+					t.Errorf("Expected call for %s to fail", name)
+				}
+			} else {
+				if result.Error != nil {
+					t.Errorf("Received unexpected error %s for %s", result.Error, name)
+				}
+			}
+		}
+	})
+}