diff --git a/Dockerfile b/Dockerfile
index 19aa30c..d009817 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -144,7 +144,7 @@ COPY src/plugin_loader.go /tmp/signal-cli-rest-api-src/
 RUN ls -la /tmp/signal-cli-rest-api-src
 RUN cd /tmp/signal-cli-rest-api-src && ${GOPATH}/bin/swag init
 RUN cd /tmp/signal-cli-rest-api-src && go build -o signal-cli-rest-api main.go
-RUN cd /tmp/signal-cli-rest-api-src && go test ./client -v
+RUN cd /tmp/signal-cli-rest-api-src && go test ./client -v && go test ./utils -v
 
 # build supervisorctl_config_creator
 RUN cd /tmp/signal-cli-rest-api-src/scripts && go build -o jsonrpc2-helper 
diff --git a/src/utils/utils.go b/src/utils/utils.go
index deec1e7..882309d 100644
--- a/src/utils/utils.go
+++ b/src/utils/utils.go
@@ -41,7 +41,7 @@ func IsPhoneNumber(s string) bool {
 				return false
 			}
 		} else {
-			if c < '0' || c > '9' {
+			if (c < '0' || c > '9') && (c != ' ') {
 				return false
 			}
 		}
diff --git a/src/utils/utils_test.go b/src/utils/utils_test.go
new file mode 100644
index 0000000..63160ff
--- /dev/null
+++ b/src/utils/utils_test.go
@@ -0,0 +1,42 @@
+package utils
+
+import (
+	"testing"
+)
+
+func expectEqual(t *testing.T, in1 bool, in2 bool) {
+	if in1 != in2 {
+		t.Errorf("got %t, wanted %t", in1, in2)
+	}
+}
+
+func TestIsPhoneNumber(t *testing.T) {
+	res := IsPhoneNumber("+12345678")	
+	expectEqual(t, res, true)
+}
+
+
+func TestIsPhoneNumberWithSpaces(t *testing.T) {
+	res := IsPhoneNumber("+ 12345678")	
+	expectEqual(t, res, true)
+}
+
+func TestIsPhoneNumberWithSpaces1(t *testing.T) {
+	res := IsPhoneNumber("+ 1234 5678")	
+	expectEqual(t, res, true)
+}
+
+func TestIsPhoneNumberWithInvalidCharacters(t *testing.T) {
+	res := IsPhoneNumber("+123456x")	
+	expectEqual(t, res, false)
+}
+
+func TestIsPhoneNumberWithMissingPrefix(t *testing.T) {
+	res := IsPhoneNumber("123456x")	
+	expectEqual(t, res, false)
+}
+
+func TestIsPhoneNumberWithInvalidCharactersAndSpaces(t *testing.T) {
+	res := IsPhoneNumber("+12345 6x")	
+	expectEqual(t, res, false)
+}