Add fuzz testing

Author: antonmedv

fuzz_test.go

@@ -0,0 +1,81 @@
+package expr_test
+
+import (
+	"os"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/antonmedv/expr"
+	"github.com/antonmedv/expr/test/playground"
+)
+
+func FuzzExpr(f *testing.F) {
+	env := playground.ExampleData()
+
+	b, err := os.ReadFile("testdata/corpus.txt")
+	if err != nil {
+		f.Fatal(err)
+	}
+	for _, testcase := range strings.Split(string(b), "\n") {
+		f.Add(testcase)
+	}
+
+	f.Add(`Posts[0].Comments[0].AuthorEmail()`)
+	f.Add(`Posts[0].Comments[0].Upvoted()`)
+	f.Add(`Posts[0].Comments[0].CommentDate.Add(now())`)
+	f.Add(`Posts[0].Comments[0].CommentDate.AddDate(0, 0, 1)`)
+	f.Add(`Authors[Posts[0].Author.ID].Profile.Biography`)
+	f.Add(`Authors[2].Profile.Age()`)
+	f.Add(`Authors[2].Profile.Website`)
+
+	okCases := []*regexp.Regexp{
+		regexp.MustCompile(`cannot slice`),
+		regexp.MustCompile(`integer divide by zero`),
+		regexp.MustCompile(`invalid operation`),
+		regexp.MustCompile(`interface conversion`),
+		regexp.MustCompile(`memory budget exceeded`),
+		regexp.MustCompile(`slice index out of range`),
+		regexp.MustCompile(`cannot fetch .* from .*`),
+		regexp.MustCompile(`cannot get .* from .*`),
+		regexp.MustCompile(`invalid argument for .*`),
+		regexp.MustCompile(`json: unsupported value`),
+		regexp.MustCompile(`error parsing regexp`),
+		regexp.MustCompile(`time: missing unit in duration`),
+		regexp.MustCompile(`using interface \{} as type .*`),
+		regexp.MustCompile(`reflect.Value.MapIndex: value of type .* is not assignable to type .*`),
+		regexp.MustCompile(`reflect: call of reflect.Value.Call on zero Value`),
+		regexp.MustCompile(`reflect: call of reflect.Value.Len on bool Value`),
+		regexp.MustCompile(`reflect: Call using .* as type .*`),
+		regexp.MustCompile(`reflect: call of reflect.Value.Index on map Value`),
+	}
+
+	skipCode := []string{
+		`??`,
+	}
+
+	f.Fuzz(func(t *testing.T, code string) {
+		for _, skipCase := range skipCode {
+			if strings.Contains(code, skipCase) {
+				t.Skip()
+				return
+			}
+		}
+
+		program, err := expr.Compile(code, expr.Env(playground.Blog{}))
+		if err != nil {
+			t.Skip()
+		}
+
+		_, err = expr.Run(program, env)
+		if err != nil {
+			for _, okCase := range okCases {
+				if okCase.MatchString(err.Error()) {
+					t.Skip()
+					return
+				}
+			}
+			t.Errorf("code: %s, err: %s", code, err)
+		}
+	})
+}

test/playground/data.go

@@ -5,7 +5,7 @@ import (
 	"time"
 )
 
-func ExampleData() interface{} {
+func ExampleData() Blog {
 	profileJohn := UserProfile{
 		Birthday:  time.Date(1990, 1, 1, 0, 0, 0, 0, time.UTC),
 		Biography: "A passionate writer about Go.",