Add search expression support to admin interface

admin/src/components/reqlog/Search.tsx

@@ -31,6 +31,7 @@ const FILTER = gql`
   query HttpRequestLogFilter {
     httpRequestLogFilter {
       onlyInScope
+      searchExpression
     }
   }
 `;
@@ -39,6 +40,7 @@ const SET_FILTER = gql`
   mutation SetHttpRequestLogFilter($filter: HttpRequestLogFilterInput) {
     setHttpRequestLogFilter(filter: $filter) {
       onlyInScope
+      searchExpression
     }
   }
 `;
@@ -75,14 +77,21 @@ const useStyles = makeStyles((theme: Theme) =>
 
 export interface SearchFilter {
   onlyInScope: boolean;
+  searchExpression: string;
 }
 
 function Search(): JSX.Element {
   const classes = useStyles();
   const theme = useTheme();
 
+  const [searchExpr, setSearchExpr] = useState("");
   const { loading: filterLoading, error: filterErr, data: filter } = useQuery(
-    FILTER
+    FILTER,
+    {
+      onCompleted: (data) => {
+        setSearchExpr(data.httpRequestLogFilter.searchExpression || "");
+      },
+    }
   );
 
   const [
@@ -111,6 +120,15 @@ function Search(): JSX.Element {
   const [filterOpen, setFilterOpen] = useState(false);
 
   const handleSubmit = (e: React.SyntheticEvent) => {
+    setFilterMutate({
+      variables: {
+        filter: {
+          ...withoutTypename(filter?.httpRequestLogFilter),
+          searchExpression: searchExpr,
+        },
+      },
+    });
+    setFilterOpen(false);
     e.preventDefault();
   };
 
@@ -142,10 +160,9 @@ function Search(): JSX.Element {
                 className={classes.iconButton}
                 onClick={() => setFilterOpen(!filterOpen)}
                 style={{
-                  color:
-                    filter?.httpRequestLogFilter !== null
-                      ? theme.palette.secondary.main
-                      : "inherit",
+                  color: filter?.httpRequestLogFilter?.onlyInScope
+                    ? theme.palette.secondary.main
+                    : "inherit",
                 }}
               >
                 {filterLoading || setFilterLoading ? (
@@ -161,6 +178,8 @@ function Search(): JSX.Element {
             <InputBase
               className={classes.input}
               placeholder="Search proxy logs…"
+              value={searchExpr}
+              onChange={(e) => setSearchExpr(e.target.value)}
               onFocus={() => setFilterOpen(true)}
             />
             <Tooltip title="Search">

pkg/api/generated.go

@@ -72,7 +72,8 @@ type ComplexityRoot struct {
 	}
 
 	HTTPRequestLogFilter struct {
-		OnlyInScope func(childComplexity int) int
+		OnlyInScope      func(childComplexity int) int
+		SearchExpression func(childComplexity int) int
 	}
 
 	HTTPResponseLog struct {
@@ -249,6 +250,13 @@ func (e *executableSchema) Complexity(typeName, field string, childComplexity in
 
 		return e.complexity.HTTPRequestLogFilter.OnlyInScope(childComplexity), true
 
+	case "HttpRequestLogFilter.searchExpression":
+		if e.complexity.HTTPRequestLogFilter.SearchExpression == nil {
+			break
+		}
+
+		return e.complexity.HTTPRequestLogFilter.SearchExpression(childComplexity), true
+
 	case "HttpResponseLog.body":
 		if e.complexity.HTTPResponseLog.Body == nil {
 			break
@@ -579,10 +587,12 @@ type ClearHTTPRequestLogResult {
 
 input HttpRequestLogFilterInput {
   onlyInScope: Boolean
+  searchExpression: String
 }
 
 type HttpRequestLogFilter {
   onlyInScope: Boolean!
+  searchExpression: String
 }
 
 type Query {
@@ -1239,6 +1249,38 @@ func (ec *executionContext) _HttpRequestLogFilter_onlyInScope(ctx context.Contex
 	return ec.marshalNBoolean2bool(ctx, field.Selections, res)
 }
 
+func (ec *executionContext) _HttpRequestLogFilter_searchExpression(ctx context.Context, field graphql.CollectedField, obj *HTTPRequestLogFilter) (ret graphql.Marshaler) {
+	defer func() {
+		if r := recover(); r != nil {
+			ec.Error(ctx, ec.Recover(ctx, r))
+			ret = graphql.Null
+		}
+	}()
+	fc := &graphql.FieldContext{
+		Object:     "HttpRequestLogFilter",
+		Field:      field,
+		Args:       nil,
+		IsMethod:   false,
+		IsResolver: false,
+	}
+
+	ctx = graphql.WithFieldContext(ctx, fc)
+	resTmp, err := ec.ResolverMiddleware(ctx, func(rctx context.Context) (interface{}, error) {
+		ctx = rctx // use context from middleware stack in children
+		return obj.SearchExpression, nil
+	})
+	if err != nil {
+		ec.Error(ctx, err)
+		return graphql.Null
+	}
+	if resTmp == nil {
+		return graphql.Null
+	}
+	res := resTmp.(*string)
+	fc.Result = res
+	return ec.marshalOString2ᚖstring(ctx, field.Selections, res)
+}
+
 func (ec *executionContext) _HttpResponseLog_requestId(ctx context.Context, field graphql.CollectedField, obj *HTTPResponseLog) (ret graphql.Marshaler) {
 	defer func() {
 		if r := recover(); r != nil {
@@ -3288,6 +3330,14 @@ func (ec *executionContext) unmarshalInputHttpRequestLogFilterInput(ctx context.
 			if err != nil {
 				return it, err
 			}
+		case "searchExpression":
+			var err error
+
+			ctx := graphql.WithPathContext(ctx, graphql.NewPathWithField("searchExpression"))
+			it.SearchExpression, err = ec.unmarshalOString2ᚖstring(ctx, v)
+			if err != nil {
+				return it, err
+			}
 		}
 	}
 
@@ -3551,6 +3601,8 @@ func (ec *executionContext) _HttpRequestLogFilter(ctx context.Context, sel ast.S
 			if out.Values[i] == graphql.Null {
 				invalids++
 			}
+		case "searchExpression":
+			out.Values[i] = ec._HttpRequestLogFilter_searchExpression(ctx, field, obj)
 		default:
 			panic("unknown field " + strconv.Quote(field.Name))
 		}

pkg/api/models_gen.go

@@ -38,11 +38,13 @@ type HTTPRequestLog struct {
 }
 
 type HTTPRequestLogFilter struct {
-	OnlyInScope bool `json:"onlyInScope"`
+	OnlyInScope      bool    `json:"onlyInScope"`
+	SearchExpression *string `json:"searchExpression"`
 }
 
 type HTTPRequestLogFilterInput struct {
-	OnlyInScope *bool `json:"onlyInScope"`
+	OnlyInScope      *bool   `json:"onlyInScope"`
+	SearchExpression *string `json:"searchExpression"`
 }
 
 type HTTPResponseLog struct {

pkg/api/resolvers.go

@@ -12,6 +12,7 @@ import (
 	"github.com/dstotijn/hetty/pkg/proj"
 	"github.com/dstotijn/hetty/pkg/reqlog"
 	"github.com/dstotijn/hetty/pkg/scope"
+	"github.com/dstotijn/hetty/pkg/search"
 	"github.com/vektah/gqlparser/v2/gqlerror"
 )
 
@@ -263,15 +264,14 @@ func (r *mutationResolver) SetHTTPRequestLogFilter(
 	ctx context.Context,
 	input *HTTPRequestLogFilterInput,
 ) (*HTTPRequestLogFilter, error) {
-	filter := findRequestsFilterFromInput(input)
+	filter, err := findRequestsFilterFromInput(input)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse request log filter: %v", err)
+	}
 	if err := r.RequestLogService.SetRequestLogFilter(ctx, filter); err != nil {
 		return nil, fmt.Errorf("could not set request log filter: %v", err)
 	}
 
-	empty := reqlog.FindRequestsFilter{}
-	if filter == empty {
-		return nil, nil
-	}
 	return findReqFilterToHTTPReqLogFilter(filter), nil
 }
 
@@ -297,13 +297,21 @@ func scopeToScopeRules(rules []scope.Rule) []ScopeRule {
 	return scopeRules
 }
 
-func findRequestsFilterFromInput(input *HTTPRequestLogFilterInput) (filter reqlog.FindRequestsFilter) {
+func findRequestsFilterFromInput(input *HTTPRequestLogFilterInput) (filter reqlog.FindRequestsFilter, err error) {
 	if input == nil {
 		return
 	}
 	if input.OnlyInScope != nil {
 		filter.OnlyInScope = *input.OnlyInScope
 	}
+	if input.SearchExpression != nil && *input.SearchExpression != "" {
+		expr, err := search.ParseQuery(*input.SearchExpression)
+		if err != nil {
+			return reqlog.FindRequestsFilter{}, fmt.Errorf("could not parse search query: %v", err)
+		}
+		filter.RawSearchExpr = *input.SearchExpression
+		filter.SearchExpr = expr
+	}
 
 	return
 }
@@ -317,5 +325,9 @@ func findReqFilterToHTTPReqLogFilter(findReqFilter reqlog.FindRequestsFilter) *H
 		OnlyInScope: findReqFilter.OnlyInScope,
 	}
 
+	if findReqFilter.RawSearchExpr != "" {
+		httpReqLogFilter.SearchExpression = &findReqFilter.RawSearchExpr
+	}
+
 	return httpReqLogFilter
 }

pkg/api/schema.graphql

@@ -64,10 +64,12 @@ type ClearHTTPRequestLogResult {
 
 input HttpRequestLogFilterInput {
   onlyInScope: Boolean
+  searchExpression: String
 }
 
 type HttpRequestLogFilter {
   onlyInScope: Boolean!
+  searchExpression: String
 }
 
 type Query {

pkg/db/sqlite/search.go

@@ -0,0 +1,108 @@
+package sqlite
+
+import (
+	"errors"
+	"fmt"
+
+	sq "github.com/Masterminds/squirrel"
+	"github.com/dstotijn/hetty/pkg/search"
+)
+
+var stringLiteralMap = map[string]string{
+	// http_requests
+	"req.id":        "req.id",
+	"req.proto":     "req.proto",
+	"req.url":       "req.url",
+	"req.method":    "req.method",
+	"req.body":      "req.body",
+	"req.timestamp": "req.timestamp",
+	// http_responses
+	"res.id":           "res.id",
+	"res.proto":        "res.proto",
+	"res.statusCode":   "res.status_code",
+	"res.statusReason": "res.status_reason",
+	"res.body":         "res.body",
+	"res.timestamp":    "res.timestamp",
+	// TODO: http_headers
+}
+
+func parseSearchExpr(expr search.Expression) (sq.Sqlizer, error) {
+	switch e := expr.(type) {
+	case *search.PrefixExpression:
+		return parsePrefixExpr(e)
+	case *search.InfixExpression:
+		return parseInfixExpr(e)
+	default:
+		return nil, fmt.Errorf("expression type (%v) not supported", expr)
+	}
+}
+
+func parsePrefixExpr(expr *search.PrefixExpression) (sq.Sqlizer, error) {
+	switch expr.Operator {
+	case search.TokOpNot:
+		// TODO: Find a way to prefix an `sq.Sqlizer` with "NOT".
+		return nil, errors.New("not implemented")
+	default:
+		return nil, errors.New("operator is not supported")
+	}
+}
+
+func parseInfixExpr(expr *search.InfixExpression) (sq.Sqlizer, error) {
+	switch expr.Operator {
+	case search.TokOpAnd:
+		left, err := parseSearchExpr(expr.Left)
+		if err != nil {
+			return nil, err
+		}
+		right, err := parseSearchExpr(expr.Right)
+		if err != nil {
+			return nil, err
+		}
+		return sq.And{left, right}, nil
+	case search.TokOpOr:
+		left, err := parseSearchExpr(expr.Left)
+		if err != nil {
+			return nil, err
+		}
+		right, err := parseSearchExpr(expr.Right)
+		if err != nil {
+			return nil, err
+		}
+		return sq.Or{left, right}, nil
+	}
+
+	left, ok := expr.Left.(*search.StringLiteral)
+	if !ok {
+		return nil, errors.New("left operand must be a string literal")
+	}
+	right, ok := expr.Right.(*search.StringLiteral)
+	if !ok {
+		return nil, errors.New("right operand must be a string literal")
+	}
+
+	mappedLeft, ok := stringLiteralMap[left.Value]
+	if !ok {
+		return nil, fmt.Errorf("invalid string literal: %v", left)
+	}
+
+	switch expr.Operator {
+	case search.TokOpEq:
+		return sq.Eq{mappedLeft: right.Value}, nil
+	case search.TokOpNotEq:
+		return sq.NotEq{mappedLeft: right.Value}, nil
+	case search.TokOpGt:
+		return sq.Gt{mappedLeft: right.Value}, nil
+	case search.TokOpLt:
+		return sq.Lt{mappedLeft: right.Value}, nil
+	case search.TokOpGtEq:
+		return sq.GtOrEq{mappedLeft: right.Value}, nil
+	case search.TokOpLtEq:
+		return sq.LtOrEq{mappedLeft: right.Value}, nil
+	case search.TokOpRe:
+		return sq.Expr(fmt.Sprintf("regexp(?, %v)", mappedLeft), right.Value), nil
+	case search.TokOpNotRe:
+		return sq.Expr(fmt.Sprintf("NOT regexp(?, %v)", mappedLeft), right.Value), nil
+	default:
+		return nil, errors.New("unsupported operator")
+	}
+}

pkg/db/sqlite/search_test.go

@@ -0,0 +1,197 @@
+package sqlite
+
+import (
+	"reflect"
+	"testing"
+
+	sq "github.com/Masterminds/squirrel"
+
+	"github.com/dstotijn/hetty/pkg/search"
+)
+
+func TestParseSearchExpr(t *testing.T) {
+	tests := []struct {
+		name            string
+		searchExpr      search.Expression
+		expectedSqlizer sq.Sqlizer
+		expectedError   error
+	}{
+		{
+			name: "req.body = bar",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpEq,
+				Left:     &search.StringLiteral{Value: "req.body"},
+				Right:    &search.StringLiteral{Value: "bar"},
+			},
+			expectedSqlizer: sq.Eq{"req.body": "bar"},
+			expectedError:   nil,
+		},
+		{
+			name: "req.body != bar",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpNotEq,
+				Left:     &search.StringLiteral{Value: "req.body"},
+				Right:    &search.StringLiteral{Value: "bar"},
+			},
+			expectedSqlizer: sq.NotEq{"req.body": "bar"},
+			expectedError:   nil,
+		},
+		{
+			name: "req.body > bar",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpGt,
+				Left:     &search.StringLiteral{Value: "req.body"},
+				Right:    &search.StringLiteral{Value: "bar"},
+			},
+			expectedSqlizer: sq.Gt{"req.body": "bar"},
+			expectedError:   nil,
+		},
+		{
+			name: "req.body < bar",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpLt,
+				Left:     &search.StringLiteral{Value: "req.body"},
+				Right:    &search.StringLiteral{Value: "bar"},
+			},
+			expectedSqlizer: sq.Lt{"req.body": "bar"},
+			expectedError:   nil,
+		},
+		{
+			name: "req.body >= bar",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpGtEq,
+				Left:     &search.StringLiteral{Value: "req.body"},
+				Right:    &search.StringLiteral{Value: "bar"},
+			},
+			expectedSqlizer: sq.GtOrEq{"req.body": "bar"},
+			expectedError:   nil,
+		},
+		{
+			name: "req.body <= bar",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpLtEq,
+				Left:     &search.StringLiteral{Value: "req.body"},
+				Right:    &search.StringLiteral{Value: "bar"},
+			},
+			expectedSqlizer: sq.LtOrEq{"req.body": "bar"},
+			expectedError:   nil,
+		},
+		{
+			name: "req.body =~ bar",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpRe,
+				Left:     &search.StringLiteral{Value: "req.body"},
+				Right:    &search.StringLiteral{Value: "bar"},
+			},
+			expectedSqlizer: sq.Expr("regexp(?, req.body)", "bar"),
+			expectedError:   nil,
+		},
+		{
+			name: "req.body !~ bar",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpNotRe,
+				Left:     &search.StringLiteral{Value: "req.body"},
+				Right:    &search.StringLiteral{Value: "bar"},
+			},
+			expectedSqlizer: sq.Expr("NOT regexp(?, req.body)", "bar"),
+			expectedError:   nil,
+		},
+		{
+			name: "req.body = bar AND res.body = yolo",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpAnd,
+				Left: &search.InfixExpression{
+					Operator: search.TokOpEq,
+					Left:     &search.StringLiteral{Value: "req.body"},
+					Right:    &search.StringLiteral{Value: "bar"},
+				},
+				Right: &search.InfixExpression{
+					Operator: search.TokOpEq,
+					Left:     &search.StringLiteral{Value: "res.body"},
+					Right:    &search.StringLiteral{Value: "yolo"},
+				},
+			},
+			expectedSqlizer: sq.And{
+				sq.Eq{"req.body": "bar"},
+				sq.Eq{"res.body": "yolo"},
+			},
+			expectedError: nil,
+		},
+		{
+			name: "req.body = bar AND res.body = yolo AND req.method = POST",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpAnd,
+				Left: &search.InfixExpression{
+					Operator: search.TokOpEq,
+					Left:     &search.StringLiteral{Value: "req.body"},
+					Right:    &search.StringLiteral{Value: "bar"},
+				},
+				Right: &search.InfixExpression{
+					Operator: search.TokOpAnd,
+					Left: &search.InfixExpression{
+						Operator: search.TokOpEq,
+						Left:     &search.StringLiteral{Value: "res.body"},
+						Right:    &search.StringLiteral{Value: "yolo"},
+					},
+					Right: &search.InfixExpression{
+						Operator: search.TokOpEq,
+						Left:     &search.StringLiteral{Value: "req.method"},
+						Right:    &search.StringLiteral{Value: "POST"},
+					},
+				},
+			},
+			expectedSqlizer: sq.And{
+				sq.Eq{"req.body": "bar"},
+				sq.And{
+					sq.Eq{"res.body": "yolo"},
+					sq.Eq{"req.method": "POST"},
+				},
+			},
+			expectedError: nil,
+		},
+		{
+			name: "req.body = bar OR res.body = yolo",
+			searchExpr: &search.InfixExpression{
+				Operator: search.TokOpOr,
+				Left: &search.InfixExpression{
+					Operator: search.TokOpEq,
+					Left:     &search.StringLiteral{Value: "req.body"},
+					Right:    &search.StringLiteral{Value: "bar"},
+				},
+				Right: &search.InfixExpression{
+					Operator: search.TokOpEq,
+					Left:     &search.StringLiteral{Value: "res.body"},
+					Right:    &search.StringLiteral{Value: "yolo"},
+				},
+			},
+			expectedSqlizer: sq.Or{
+				sq.Eq{"req.body": "bar"},
+				sq.Eq{"res.body": "yolo"},
+			},
+			expectedError: nil,
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got, err := parseSearchExpr(tt.searchExpr)
+			assertError(t, tt.expectedError, err)
+			if !reflect.DeepEqual(tt.expectedSqlizer, got) {
+				t.Errorf("expected: %#v, got: %#v", tt.expectedSqlizer, got)
+			}
+		})
+	}
+}
+
+func assertError(t *testing.T, exp, got error) {
+	switch {
+	case exp == nil && got != nil:
+		t.Fatalf("expected: nil, got: %v", got)
+	case exp != nil && got == nil:
+		t.Fatalf("expected: %v, got: nil", exp.Error())
+	case exp != nil && got != nil && exp.Error() != got.Error():
+		t.Fatalf("expected: %v, got: %v", exp.Error(), got.Error())
+	}
+}

pkg/db/sqlite/sqlite.go

@@ -30,7 +30,7 @@ var regexpFn = func(pattern string, value interface{}) (bool, error) {
 	case string:
 		return regexp.MatchString(pattern, v)
 	case int64:
-		return regexp.MatchString(pattern, string(v))
+		return regexp.MatchString(pattern, fmt.Sprintf("%v", v))
 	case []byte:
 		return regexp.Match(pattern, v)
 	default:
@@ -257,6 +257,14 @@ func (c *Client) FindRequestLogs(
 		}
 	}
 
+	if filter.SearchExpr != nil {
+		sqlizer, err := parseSearchExpr(filter.SearchExpr)
+		if err != nil {
+			return nil, fmt.Errorf("sqlite: could not parse search expression: %v", err)
+		}
+		reqQuery = reqQuery.Where(sqlizer)
+	}
+
 	sql, args, err := reqQuery.ToSql()
 	if err != nil {
 		return nil, fmt.Errorf("sqlite: could not parse query: %v", err)

pkg/reqlog/reqlog.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"compress/gzip"
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io/ioutil"
@@ -14,6 +15,7 @@ import (
 	"github.com/dstotijn/hetty/pkg/proj"
 	"github.com/dstotijn/hetty/pkg/proxy"
 	"github.com/dstotijn/hetty/pkg/scope"
+	"github.com/dstotijn/hetty/pkg/search"
 )
 
 type contextKey int
@@ -51,7 +53,9 @@ type Service struct {
 }
 
 type FindRequestsFilter struct {
-	OnlyInScope bool
+	OnlyInScope   bool
+	SearchExpr    search.Expression `json:"-"`
+	RawSearchExpr string
 }
 
 type Config struct {
@@ -210,6 +214,34 @@ func (svc *Service) ResponseModifier(next proxy.ResponseModifyFunc) proxy.Respon
 	}
 }
 
+// UnmarshalJSON implements json.Unmarshaler.
+func (f *FindRequestsFilter) UnmarshalJSON(b []byte) error {
+	var dto struct {
+		OnlyInScope   bool
+		RawSearchExpr string
+	}
+	if err := json.Unmarshal(b, &dto); err != nil {
+		return err
+	}
+
+	filter := FindRequestsFilter{
+		OnlyInScope:   dto.OnlyInScope,
+		RawSearchExpr: dto.RawSearchExpr,
+	}
+
+	if dto.RawSearchExpr != "" {
+		expr, err := search.ParseQuery(dto.RawSearchExpr)
+		if err != nil {
+			return err
+		}
+		filter.SearchExpr = expr
+	}
+
+	*f = filter
+
+	return nil
+}
+
 func (svc *Service) loadSettings() error {
 	return svc.repo.FindSettingsByModule(context.Background(), moduleName, svc)
 }

pkg/search/parser.go

@@ -9,10 +9,10 @@ type precedence int
 const (
 	_ precedence = iota
 	precLowest
-	precEq
 	precAnd
 	precOr
 	precNot
+	precEq
 	precLessGreater
 	precPrefix
 	precGroup
@@ -86,7 +86,7 @@ func ParseQuery(input string) (expr Expression, err error) {
 	p.nextToken()
 
 	if p.curTokenIs(TokEOF) {
-		return nil, fmt.Errorf("unexpected EOF")
+		return nil, fmt.Errorf("search: unexpected EOF")
 	}
 
 	for !p.curTokenIs(TokEOF) {

pkg/search/parser_test.go

@@ -17,7 +17,7 @@ func TestParseQuery(t *testing.T) {
 			name:               "empty query",
 			input:              "",
 			expectedExpression: nil,
-			expectedError:      errors.New("unexpected EOF"),
+			expectedError:      errors.New("search: unexpected EOF"),
 		},
 		{
 			name:               "string literal expression",
@@ -199,6 +199,24 @@ func TestParseQuery(t *testing.T) {
 			},
 			expectedError: nil,
 		},
+		{
+			name:  "eq operator takes precedence over boolean ops",
+			input: "foo=bar OR baz=yolo",
+			expectedExpression: &InfixExpression{
+				Operator: TokOpOr,
+				Left: &InfixExpression{
+					Operator: TokOpEq,
+					Left:     &StringLiteral{Value: "foo"},
+					Right:    &StringLiteral{Value: "bar"},
+				},
+				Right: &InfixExpression{
+					Operator: TokOpEq,
+					Left:     &StringLiteral{Value: "baz"},
+					Right:    &StringLiteral{Value: "yolo"},
+				},
+			},
+			expectedError: nil,
+		},
 	}
 
 	for _, tt := range tests {