5 files changed, 226 insertions, 0 deletions
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
new file mode 100644
index 0000000..36b2e97
--- /dev/null
+++ b/internal/config/config_test.go
@@ -0,0 +1,208 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func noSystemConfig(t *testing.T) {
+	t.Helper()
+	old := systemConfigPath
+	systemConfigPath = filepath.Join(t.TempDir(), "absent.conf")
+	t.Cleanup(func() { systemConfigPath = old })
+}
+
+func writeConf(t *testing.T, body string) string {
+	t.Helper()
+	path := filepath.Join(t.TempDir(), "openstore.conf")
+	if err := os.WriteFile(path, []byte(body), 0o644); err != nil {
+		t.Fatalf("write conf: %v", err)
+	}
+	return path
+}
+
+func TestLoadMissingFileUsesDefaults(t *testing.T) {
+	noSystemConfig(t)
+
+	cfg, err := Load(filepath.Join(t.TempDir(), "nonexistent.conf"))
+	if err != nil {
+		t.Fatalf("load with no config file failed: %v", err)
+	}
+
+	if cfg.Serve.Addr != ":3000" {
+		t.Errorf("addr: got %q, want \":3000\"", cfg.Serve.Addr)
+	}
+	if cfg.Instance.Name != "Openstore" {
+		t.Errorf("name: got %q, want \"Openstore\"", cfg.Instance.Name)
+	}
+}
+
+func TestLoadFullFileOverridesDefaults(t *testing.T) {
+	noSystemConfig(t)
+
+	cfg, err := Load("testdata/full.conf")
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+
+	tests := []struct {
+		field string
+		got   string
+		want  string
+	}{
+		{"addr", cfg.Serve.Addr, "127.0.0.1:8080"},
+		{"name", cfg.Instance.Name, "Full Store"},
+		{"contact-email", cfg.Instance.ContactEmail, "full@store.com"},
+		{"base-url", cfg.Instance.BaseURL, "https://full.store.com"},
+	}
+
+	for _, tt := range tests {
+		if tt.got != tt.want {
+			t.Errorf("%s: got %q, want %q", tt.field, tt.got, tt.want)
+		}
+	}
+}
+
+func TestLoadPartialFileKeepsDefaults(t *testing.T) {
+	noSystemConfig(t)
+
+	cfg, err := Load("testdata/partial.conf")
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+
+	if cfg.Instance.Name != "Only Name Set" {
+		t.Errorf("name: got %q, want \"Only Name Set\"", cfg.Instance.Name)
+	}
+	if cfg.Serve.Addr != ":3000" {
+		t.Errorf("unset addr should keep default, got %q", cfg.Serve.Addr)
+	}
+	if cfg.Instance.BaseURL != "https://www.example.com" {
+		t.Errorf("unset base-url should keep default, got %q", cfg.Instance.BaseURL)
+	}
+}
+
+func TestLoadUserConfigWinsOverSystem(t *testing.T) {
+	old := systemConfigPath
+	systemConfigPath = "testdata/system.conf"
+	t.Cleanup(func() { systemConfigPath = old })
+
+	cfg, err := Load("testdata/partial.conf")
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+
+	if cfg.Instance.Name != "Only Name Set" {
+		t.Errorf("user config should win, got name %q", cfg.Instance.Name)
+	}
+	if cfg.Instance.ContactEmail != "system@store.com" {
+		t.Errorf("key absent from user config should fall back to system, got %q",
+			cfg.Instance.ContactEmail)
+	}
+	if cfg.Serve.Addr != "127.0.0.1:9999" {
+		t.Errorf("section absent from user config should fall back to system, got %q",
+			cfg.Serve.Addr)
+	}
+}
+
+func TestLoadMalformedFile(t *testing.T) {
+	noSystemConfig(t)
+
+	if _, err := Load("testdata/malformed.conf"); err == nil {
+		t.Error("malformed config file loaded without error")
+	}
+}
+
+func TestLoadRejectsBadBaseURL(t *testing.T) {
+	noSystemConfig(t)
+
+	tests := map[string]string{
+		"not a url":      "garbage",
+		"no scheme":      "example.com/path",
+		"scheme only":    "https://",
+		"path only":      "/listings",
+		"bad url syntax": "://x",
+	}
+
+	for name, badURL := range tests {
+		t.Run(name, func(t *testing.T) {
+			path := writeConf(t, "[instance]\nbase-url = "+badURL+"\n")
+
+			_, err := Load(path)
+			if err == nil {
+				t.Fatalf("bad base-url %q accepted", badURL)
+			}
+			if !strings.Contains(err.Error(), "base-url") {
+				t.Errorf("error should mention base-url, got: %v", err)
+			}
+		})
+	}
+}
+
+func TestLoadEmptyValueKeepsDefault(t *testing.T) {
+	noSystemConfig(t)
+
+	path := writeConf(t, "[instance]\nname = \nbase-url = \n")
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+
+	if cfg.Instance.Name != "Openstore" {
+		t.Errorf("empty value should leave default, got name %q", cfg.Instance.Name)
+	}
+	if cfg.Instance.BaseURL != "https://www.example.com" {
+		t.Errorf("empty value should leave default, got base-url %q", cfg.Instance.BaseURL)
+	}
+}
+
+func TestLoadAcceptsGoodBaseURL(t *testing.T) {
+	noSystemConfig(t)
+
+	urls := []string{
+		"https://example.com",
+		"http://example.com",
+		"https://example.com/subpath",
+		"https://sub.example.com:8443",
+	}
+
+	for _, u := range urls {
+		t.Run(u, func(t *testing.T) {
+			path := writeConf(t, "[instance]\nbase-url = "+u+"\n")
+
+			cfg, err := Load(path)
+			if err != nil {
+				t.Fatalf("good base-url %q rejected: %v", u, err)
+			}
+			if cfg.Instance.BaseURL != u {
+				t.Errorf("base-url: got %q, want %q", cfg.Instance.BaseURL, u)
+			}
+		})
+	}
+}
+
+func TestDefaultPath(t *testing.T) {
+	t.Setenv("XDG_CONFIG_HOME", "/tmp/xdg-test")
+
+	path, err := DefaultPath()
+	if err != nil {
+		t.Fatalf("DefaultPath: %v", err)
+	}
+
+	want := filepath.Join("/tmp/xdg-test", "openstore", "openstore.conf")
+	if path != want {
+		t.Errorf("got %q, want %q", path, want)
+	}
+}
+
+func TestDefaultPathWithoutConfigDir(t *testing.T) {
+	t.Setenv("XDG_CONFIG_HOME", "")
+	t.Setenv("HOME", "")
+
+	if _, err := DefaultPath(); err == nil {
+		t.Error("DefaultPath returned no error with no config dir available")
+	}
+}
diff --git a/internal/config/testdata/full.conf b/internal/config/testdata/full.conf
new file mode 100644
index 0000000..1f703f0
--- /dev/null
+++ b/internal/config/testdata/full.conf
@@ -0,0 +1,7 @@
+[serve]
+addr = 127.0.0.1:8080
+
+[instance]
+name = Full Store
+contact-email = full@store.com
+base-url = https://full.store.com
diff --git a/internal/config/testdata/malformed.conf b/internal/config/testdata/malformed.conf
new file mode 100644
index 0000000..327aace
--- /dev/null
+++ b/internal/config/testdata/malformed.conf
@@ -0,0 +1,2 @@
+[instance
+name = Unclosed Section
diff --git a/internal/config/testdata/partial.conf b/internal/config/testdata/partial.conf
new file mode 100644
index 0000000..e84544d
--- /dev/null
+++ b/internal/config/testdata/partial.conf
@@ -0,0 +1,2 @@
+[instance]
+name = Only Name Set
diff --git a/internal/config/testdata/system.conf b/internal/config/testdata/system.conf
new file mode 100644
index 0000000..f2533a8
--- /dev/null
+++ b/internal/config/testdata/system.conf
@@ -0,0 +1,7 @@
+[serve]
+addr = 127.0.0.1:9999
+
+[instance]
+name = System Store
+contact-email = system@store.com
+base-url = https://system.store.com