feat: config parsing

internal/config/config.go

@@ -0,0 +1,40 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/BurntSushi/toml"
+)
+
+type Config struct {
+	TestDir    string
+	HasTestDir bool
+}
+
+type tomlConfig struct {
+	Miro tomlMiroConfig `toml:"miro"`
+}
+
+type tomlMiroConfig struct {
+	TestDir string `toml:"test_dir"`
+}
+
+// ReadConfig reads miro.toml and reports whether [miro].test_dir was explicitly set.
+func ReadConfig(path string) (Config, error) {
+	var raw tomlConfig
+
+	meta, err := toml.DecodeFile(path, &raw)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return Config{}, err
+		}
+		return Config{}, fmt.Errorf("failed to read %s: %v", path, err)
+	}
+
+	return Config{
+		TestDir:    raw.Miro.TestDir,
+		HasTestDir: meta.IsDefined("miro", "test_dir"),
+	}, nil
+}