add unit tests for validating config template (#94)

* add unit tests for validating config template

* add defensive check

* update asserts

config/config.template.yml

@@ -46,4 +46,3 @@ experimental_proxy_mode: false
 trusted_packages:
   - purl: pkg:npm/@safedep/pmg
     reason: "PMG is a trusted package for PMG"
-

config/config_template_test.go

@@ -0,0 +1,63 @@
+package config
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
+	"go.yaml.in/yaml/v3"
+)
+
+func TestTemplateParsesAsYAML(t *testing.T) {
+	var cfg Config
+
+	// Defensive check: Ensure template is valid YAML (not used for mapstructure mapping)
+	var raw map[string]any
+	err := yaml.Unmarshal([]byte(templateConfig), &raw)
+	assert.NoError(t, err, "templateConfig must be valid YAML")
+
+	// Ensure Viper (mapstructure) maps to Config as expected
+	v := viper.New()
+	v.SetConfigType("yaml")
+	err = v.ReadConfig(strings.NewReader(templateConfig))
+	assert.NoError(t, err, "expected no error while reading config")
+
+	err = v.Unmarshal(&cfg)
+	assert.NoError(t, err, "expected no error while unmarshalling config")
+
+	assert.True(t, true, cfg.Transitive, "expected Transitive true")
+	assert.Equal(t, 5, cfg.TransitiveDepth, "expected TransitiveDepth 5")
+	assert.False(t, false, cfg.IncludeDevDependencies, "expected IncludeDevDependencies false")
+	assert.False(t, false, cfg.Paranoid, "expected Paranoid false")
+	assert.False(t, false, cfg.SkipEventLogging, "expected SkipEventLogging false")
+	assert.Equal(t, 7, cfg.EventLogRetentionDays, "expected EventLogRetentionDays 7")
+	assert.Len(t, cfg.TrustedPackages, 1)
+}
+
+func TestTemplateMatchesDefaults(t *testing.T) {
+	var parsed Config
+
+	v := viper.New()
+	v.SetConfigType("yaml")
+	err := v.ReadConfig(strings.NewReader(templateConfig))
+	assert.NoError(t, err, "expected no error while reading config")
+
+	err = v.Unmarshal(&parsed)
+	assert.NoError(t, err, "expected no error while unmarshalling config")
+
+	def := DefaultConfig().Config
+
+	assert.Equal(t, def.Transitive, parsed.Transitive, "transitive mismatch")
+	assert.Equal(t, def.TransitiveDepth, parsed.TransitiveDepth, "transitive_depth mismatch")
+	assert.Equal(t, def.IncludeDevDependencies, parsed.IncludeDevDependencies, "include_dev_dependencies mismatch")
+	assert.Equal(t, def.Paranoid, parsed.Paranoid, "paranoid mismatch")
+	assert.Equal(t, def.SkipEventLogging, parsed.SkipEventLogging, "skip_event_logging mismatch")
+	assert.Equal(t, def.EventLogRetentionDays, parsed.EventLogRetentionDays, "event_log_retention_days mismatch")
+
+	assert.NotEmpty(t, parsed.TrustedPackages, "expected at least one trusted_packages entry")
+
+	first := parsed.TrustedPackages[0]
+	assert.NotEmpty(t, first.Purl, "first trusted package has empty purl")
+	assert.NotEmpty(t, first.Reason, "first trusted package has empty reason")
+}