diff --git a/pkg/engine/assert/expression_test.go b/pkg/engine/assert/expression_test.go
index 401ea183..20e8c1a3 100644
--- a/pkg/engine/assert/expression_test.go
+++ b/pkg/engine/assert/expression_test.go
@@ -2,8 +2,9 @@ package assert
 
 import (
 	"context"
-	"reflect"
 	"testing"
+
+	tassert "github.com/stretchr/testify/assert"
 )
 
 func Test_parseExpressionRegex(t *testing.T) {
@@ -170,9 +171,8 @@ func Test_parseExpressionRegex(t *testing.T) {
 	}}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := parseExpressionRegex(context.Background(), tt.in); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("parseExpressionRegex() = %v, want %v", got, tt.want)
-			}
+			got := parseExpressionRegex(context.Background(), tt.in)
+			tassert.Equal(t, tt.want, got)
 		})
 	}
 }
diff --git a/pkg/engine/assert/project.go b/pkg/engine/assert/project.go
index 788934c8..38fd1fbb 100644
--- a/pkg/engine/assert/project.go
+++ b/pkg/engine/assert/project.go
@@ -2,7 +2,6 @@ package assert
 
 import (
 	"context"
-	"fmt"
 	"reflect"
 
 	"github.com/jmespath-community/go-jmespath/pkg/binding"
@@ -33,26 +32,28 @@ func project(ctx context.Context, key interface{}, value interface{}, bindings b
 			}, nil
 		} else {
 			if reflectutils.GetKind(value) == reflect.Map {
-				projected := reflect.ValueOf(value).MapIndex(reflect.ValueOf(expression.statement))
-				if !projected.IsValid() {
-					return nil, fmt.Errorf("failed to find the map index `%s`", expression.statement)
+				mapValue := reflect.ValueOf(value).MapIndex(reflect.ValueOf(expression.statement))
+				var value interface{}
+				if mapValue.IsValid() {
+					value = mapValue.Interface()
 				}
 				return &projection{
 					foreach:     expression.foreach,
 					foreachName: expression.foreachName,
 					binding:     expression.binding,
-					result:      projected.Interface(),
+					result:      value,
 				}, nil
 			}
 		}
 	}
 	if reflectutils.GetKind(value) == reflect.Map {
-		projected := reflect.ValueOf(value).MapIndex(reflect.ValueOf(key))
-		if !projected.IsValid() {
-			return nil, fmt.Errorf("failed to find the map index `%v`", key)
+		mapValue := reflect.ValueOf(value).MapIndex(reflect.ValueOf(key))
+		var value interface{}
+		if mapValue.IsValid() {
+			value = mapValue.Interface()
 		}
 		return &projection{
-			result: projected.Interface(),
+			result: value,
 		}, nil
 	}
 	// TODO is this an error ?
diff --git a/pkg/engine/assert/project_test.go b/pkg/engine/assert/project_test.go
new file mode 100644
index 00000000..ca164c10
--- /dev/null
+++ b/pkg/engine/assert/project_test.go
@@ -0,0 +1,40 @@
+package assert
+
+import (
+	"context"
+	"testing"
+
+	"github.com/jmespath-community/go-jmespath/pkg/binding"
+	tassert "github.com/stretchr/testify/assert"
+)
+
+func Test_project(t *testing.T) {
+	tests := []struct {
+		name     string
+		key      interface{}
+		value    interface{}
+		bindings binding.Bindings
+		want     *projection
+		wantErr  bool
+	}{{
+		name: "map index not found",
+		key:  "foo",
+		value: map[string]interface{}{
+			"bar": 42,
+		},
+		bindings: nil,
+		want:     nil,
+		wantErr:  false,
+	}}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := project(context.TODO(), tt.key, tt.value, tt.bindings)
+			if tt.wantErr {
+				tassert.Error(t, err)
+				tassert.Equal(t, tt.want, got)
+			} else {
+				tassert.NoError(t, err)
+			}
+		})
+	}
+}