implement the HTTP/3 error codes

http3/error_codes_test.go

@@ -0,0 +1,43 @@
+package http3
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"path"
+	"runtime"
+	"strconv"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("error codes", func() {
+	It("has a string representation for every error code", func() {
+		// We parse the error code file, extract all constants, and verify that
+		// each of them has a string version. Go FTW!
+		_, thisfile, _, ok := runtime.Caller(0)
+		if !ok {
+			panic("Failed to get current frame")
+		}
+		filename := path.Join(path.Dir(thisfile), "error_codes.go")
+		fileAst, err := parser.ParseFile(token.NewFileSet(), filename, nil, 0)
+		Expect(err).NotTo(HaveOccurred())
+		constSpecs := fileAst.Decls[2].(*ast.GenDecl).Specs
+		Expect(len(constSpecs)).To(BeNumerically(">", 4)) // at time of writing
+		for _, c := range constSpecs {
+			valString := c.(*ast.ValueSpec).Values[0].(*ast.BasicLit).Value
+			val, err := strconv.ParseInt(valString, 0, 64)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(errorCode(val).String()).ToNot(Equal("unknown error code"))
+		}
+	})
+
+	It("has a string represenation for frame parsing errors", func() {
+		Expect(errorCode(0x142).String()).To(Equal("HTTP_MALFORMED_FRAME: 0x42"))
+	})
+
+	It("has a string representation for unknown error codes", func() {
+		Expect(errorCode(0x1337).String()).To(Equal("unknown error code: 0x1337"))
+	})
+})