diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index 6c192f969..70b6db6d9 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -66,6 +66,7 @@ jobs:
       env:
         GOARCH: '386'
     - run: go test ./...
+    - run: go test -count=2 ./...
     - run: go test -v -run TestRaceyPatternSchema -race ./...
       env:
         CGO_ENABLED: '1'
diff --git a/openapi3/schema_formats.go b/openapi3/schema_formats.go
index 29fbd51fb..17b7564cf 100644
--- a/openapi3/schema_formats.go
+++ b/openapi3/schema_formats.go
@@ -12,18 +12,19 @@ const (
 	FormatOfStringForUUIDOfRFC4122 = `^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$`
 )
 
-//FormatCallback custom check on exotic formats
-type FormatCallback func(Val string) error
+// FormatCallback performs custom checks on exotic formats
+type FormatCallback func(value string) error
 
+// Format represents a format validator registered by either DefineStringFormat or DefineStringFormatCallback
 type Format struct {
 	regexp   *regexp.Regexp
 	callback FormatCallback
 }
 
-//SchemaStringFormats allows for validating strings format
-var SchemaStringFormats = make(map[string]Format, 8)
+// SchemaStringFormats allows for validating string formats
+var SchemaStringFormats = make(map[string]Format, 4)
 
-//DefineStringFormat Defines a new regexp pattern for a given format
+// DefineStringFormat defines a new regexp pattern for a given format
 func DefineStringFormat(name string, pattern string) {
 	re, err := regexp.Compile(pattern)
 	if err != nil {
diff --git a/openapi3/schema_formats_test.go b/openapi3/schema_formats_test.go
index 14733c8a1..5cceb8cf0 100644
--- a/openapi3/schema_formats_test.go
+++ b/openapi3/schema_formats_test.go
@@ -13,6 +13,9 @@ func TestIssue430(t *testing.T) {
 		NewStringSchema().WithFormat("ipv6"),
 	)
 
+	delete(SchemaStringFormats, "ipv4")
+	delete(SchemaStringFormats, "ipv6")
+
 	err := schema.Validate(context.Background())
 	require.NoError(t, err)