feat(checker): port other checkers over

Signed-off-by: Xe Iaso <me@xeiaso.net>

lib/checker/headermatches/config_test.go

@@ -0,0 +1,55 @@
+package headermatches
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestFileConfigValid(t *testing.T) {
+	for _, tt := range []struct {
+		name, description string
+		in                fileConfig
+		err               error
+	}{
+		{
+			name:        "simple happy",
+			description: "the most common usecase",
+			in: fileConfig{
+				Header:     "User-Agent",
+				ValueRegex: ".*",
+			},
+		},
+		{
+			name:        "no header",
+			description: "Header must be set, it is not",
+			in: fileConfig{
+				ValueRegex: ".*",
+			},
+			err: ErrNoHeader,
+		},
+		{
+			name:        "no value regex",
+			description: "ValueRegex must be set, it is not",
+			in: fileConfig{
+				Header: "User-Agent",
+			},
+			err: ErrNoValueRegex,
+		},
+		{
+			name:        "invalid regex",
+			description: "the user wrote an invalid value regular expression",
+			in: fileConfig{
+				Header:     "User-Agent",
+				ValueRegex: "[a-z",
+			},
+			err: ErrInvalidRegex,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := tt.in.Valid(); !errors.Is(err, tt.err) {
+				t.Log(tt.description)
+				t.Fatal(err)
+			}
+		})
+	}
+}