Add tests for config.

config_test.go

@@ -0,0 +1,161 @@
+package main
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestReadConfig(t *testing.T) {
+	t.Run("valid config", func(t *testing.T) {
+		file, err := os.CreateTemp(os.TempDir(), "connectbox-exporter.yaml")
+		require.NoError(t, err)
+		defer os.Remove(file.Name())
+
+		_, err = file.WriteString(
+			"listen_addr: 0.0.0.0:9119\n" +
+				"targets:\n" +
+				"  - addr: 192.168.178.1\n" +
+				"    username: NULL\n" +
+				"    password: password",
+		)
+		require.NoError(t, err)
+
+		err = file.Close()
+		require.NoError(t, err)
+
+		conf, err := ReadConfig(file.Name())
+		require.NoError(t, err)
+
+		want := Config{
+			ListenAddr: "0.0.0.0:9119",
+			Targets: []Target{{
+				Addr:     "192.168.178.1",
+				Username: "NULL",
+				Password: "password",
+			}},
+		}
+		require.Equal(t, want, conf)
+	})
+
+	t.Run("empty listen address", func(t *testing.T) {
+		file, err := os.CreateTemp(os.TempDir(), "connectbox-exporter.yaml")
+		require.NoError(t, err)
+		defer os.Remove(file.Name())
+
+		_, err = file.WriteString(
+			"targets:\n" +
+				"  - addr: 192.168.178.1\n" +
+				"    username: NULL\n" +
+				"    password: password",
+		)
+		require.NoError(t, err)
+
+		err = file.Close()
+		require.NoError(t, err)
+
+		conf, err := ReadConfig(file.Name())
+		require.NoError(t, err)
+
+		want := Config{
+			ListenAddr: "0.0.0.0:9119",
+			Targets: []Target{{
+				Addr:     "192.168.178.1",
+				Username: "NULL",
+				Password: "password",
+			}},
+		}
+		require.Equal(t, want, conf)
+	})
+
+	t.Run("empty target address", func(t *testing.T) {
+		file, err := os.CreateTemp(os.TempDir(), "connectbox-exporter.yaml")
+		require.NoError(t, err)
+		defer os.Remove(file.Name())
+
+		_, err = file.WriteString(
+			"listen_addr: 0.0.0.0:9119\n" +
+				"targets:\n" +
+				"  - username: NULL\n" +
+				"    password: password",
+		)
+		require.NoError(t, err)
+
+		err = file.Close()
+		require.NoError(t, err)
+
+		_, err = ReadConfig(file.Name())
+		require.ErrorContains(t, err, "found target with empty address")
+	})
+
+	t.Run("empty target username", func(t *testing.T) {
+		file, err := os.CreateTemp(os.TempDir(), "connectbox-exporter.yaml")
+		require.NoError(t, err)
+		defer os.Remove(file.Name())
+
+		_, err = file.WriteString(
+			"listen_addr: 0.0.0.0:9119\n" +
+				"targets:\n" +
+				"  - addr: 192.168.178.1\n" +
+				"    password: password",
+		)
+		require.NoError(t, err)
+
+		err = file.Close()
+		require.NoError(t, err)
+
+		conf, err := ReadConfig(file.Name())
+		require.NoError(t, err)
+
+		want := Config{
+			ListenAddr: "0.0.0.0:9119",
+			Targets: []Target{{
+				Addr:     "192.168.178.1",
+				Username: "NULL",
+				Password: "password",
+			}},
+		}
+		require.Equal(t, want, conf)
+	})
+
+	t.Run("empty target password", func(t *testing.T) {
+		file, err := os.CreateTemp(os.TempDir(), "connectbox-exporter.yaml")
+		require.NoError(t, err)
+		defer os.Remove(file.Name())
+
+		_, err = file.WriteString(
+			"listen_addr: 0.0.0.0:9119\n" +
+				"targets:\n" +
+				"  - addr: 192.168.178.1\n" +
+				"    username: NULL",
+		)
+		require.NoError(t, err)
+
+		err = file.Close()
+		require.NoError(t, err)
+
+		_, err = ReadConfig(file.Name())
+		require.ErrorContains(t, err, "found target with empty password")
+	})
+
+	t.Run("invalid yaml", func(t *testing.T) {
+		file, err := os.CreateTemp(os.TempDir(), "connectbox-exporter.yaml")
+		require.NoError(t, err)
+		defer os.Remove(file.Name())
+
+		_, err = file.WriteString("hello: world: !")
+		require.NoError(t, err)
+
+		err = file.Close()
+		require.NoError(t, err)
+
+		_, err = ReadConfig(file.Name())
+		require.ErrorContains(t, err, "unmarshal file")
+	})
+
+	t.Run("non-existing config file", func(t *testing.T) {
+		_, err := ReadConfig("not-exists.yaml")
+		require.ErrorContains(t, err, "no such file or directory")
+	})
+}