pkg/testutils: Add check for golden file name creator

This commit is required to make future additions of
the golden files compatible with the Go module restrictions
on file names.

Every existing file returned by a pattern `*.golden.*` has
been checked against the `module.CheckFilePath()` to ensure
that all existing ones are compliant with the Go module
restrictions.

This commit adds a dependency on the golang.org/x/mod package.

See:
- https://go.dev/ref/mod#zip-path-size-constraints

go.mod

@@ -45,6 +45,7 @@ require (
 	go.uber.org/multierr v1.6.0
 	go.uber.org/zap v1.21.0
 	golang.org/x/crypto v0.0.0-20201112155050-0c6587e931a9
+	golang.org/x/mod v0.4.2
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
 	golang.org/x/sys v0.0.0-20210510120138-977fb7262007
 	golang.org/x/tools v0.1.5

go.sum

@@ -877,6 +877,7 @@ golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzB
 golang.org/x/mod v0.1.1-0.20191107180719-034126e5016b/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/mod v0.4.2 h1:Gz96sIWK3OalVv/I/qNygP42zyoKp3xptRVCWRFEBvo=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=

pkg/testutils/golden.go

@@ -10,6 +10,8 @@ import (
 	"path"
 	"strings"
 	"testing"
+
+	"golang.org/x/mod/module"
 )
 
 var flagUpdate = flag.Bool("update", false, "update .golden files")
@@ -40,10 +42,14 @@ func SaveGoldenJSONFileIfNeeded(tb testing.TB, v interface{}) {
 		tb.Fatal(err)
 	}
 
-	if err := os.MkdirAll(path.Dir(goldenJSONFileName(tb)), 0o777); err != nil {
+	filename := goldenJSONFileName(tb)
+	if err := module.CheckFilePath(filename); err != nil {
+		tb.Fatalf("cannot use name of the test to store golden file %q: %v", filename, err)
+	}
+	if err := os.MkdirAll(path.Dir(filename), 0o777); err != nil {
 		tb.Fatal(err)
 	}
-	if err := os.WriteFile(goldenJSONFileName(tb), buf.Bytes(), 0o666); err != nil {
+	if err := os.WriteFile(filename, buf.Bytes(), 0o666); err != nil {
 		tb.Error(err)
 	}
 }
@@ -76,10 +82,14 @@ func SaveGoldenTextFileIfNeeded(tb testing.TB, s string) {
 		return
 	}
 
-	if err := os.MkdirAll(path.Dir(goldenTextFileName(tb)), 0o777); err != nil {
+	filename := goldenTextFileName(tb)
+	if err := module.CheckFilePath(filename); err != nil {
+		tb.Fatalf("cannot use name of the test to store golden file %q: %v", filename, err)
+	}
+	if err := os.MkdirAll(path.Dir(filename), 0o777); err != nil {
 		tb.Fatal(err)
 	}
-	if err := os.WriteFile(goldenTextFileName(tb), []byte(s), 0o666); err != nil {
+	if err := os.WriteFile(filename, []byte(s), 0o666); err != nil {
 		tb.Error(err)
 	}
 }