Annotation support

Provide support for annotations in faasd with namespaced container
labels. Unit tested and confirmed with end to end test via faasd
deployed to multipass VM

Signed-off-by: Alex Tomic <atomic777@gmail.com>

pkg/provider/handlers/deploy_test.go

@@ -0,0 +1,63 @@
+package handlers
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/openfaas/faas-provider/types"
+)
+
+func Test_BuildLabels_WithAnnotations(t *testing.T) {
+	// Test each combination of nil/non-nil annotation + label
+	tables := []struct {
+		label      map[string]string
+		annotation map[string]string
+		result     map[string]string
+	}{
+		{nil, nil, map[string]string{}},
+		{map[string]string{"L1": "V1"}, nil, map[string]string{"L1": "V1"}},
+		{nil, map[string]string{"A1": "V2"}, map[string]string{fmt.Sprintf("%sA1", annotationLabelPrefix): "V2"}},
+		{
+			map[string]string{"L1": "V1"}, map[string]string{"A1": "V2"},
+			map[string]string{"L1": "V1", fmt.Sprintf("%sA1", annotationLabelPrefix): "V2"},
+		},
+	}
+
+	for _, pair := range tables {
+
+		request := &types.FunctionDeployment{
+			Labels:      &pair.label,
+			Annotations: &pair.annotation,
+		}
+
+		val, err := buildLabels(request)
+
+		if err != nil {
+			t.Fatalf("want: no error got: %v", err)
+		}
+
+		if !reflect.DeepEqual(val, pair.result) {
+			t.Errorf("Got: %s, expected %s", val, pair.result)
+		}
+	}
+
+}
+
+func Test_BuildLabels_WithAnnotationCollision(t *testing.T) {
+	request := &types.FunctionDeployment{
+		Labels: &map[string]string{
+			"function_name": "echo",
+			fmt.Sprintf("%scurrent-time", annotationLabelPrefix): "Wed 25 Jul 06:41:43 BST 2018",
+		},
+		Annotations: &map[string]string{"current-time": "Wed 25 Jul 06:41:43 BST 2018"},
+	}
+
+	val, err := buildLabels(request)
+
+	fmt.Printf("%s, %s\n", val, err)
+	if err == nil {
+		t.Errorf("Expected an error, got %d values", len(val))
+	}
+
+}