fix: cache ttl interpolation

internal/config/environment_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"testing"
+	"time"
 
 	"github.com/pkg/errors"
 	"gopkg.in/yaml.v3"
@@ -65,7 +66,7 @@ func TestInterpolatedMap(t *testing.T) {
 			var interpolatedMap InterpolatedMap
 
 			if tc.Env != nil {
-				interpolatedMap.getEnv = func(key string) string {
+				getEnv = func(key string) string {
 					return tc.Env[key]
 				}
 			}
@@ -80,3 +81,54 @@ func TestInterpolatedMap(t *testing.T) {
 		})
 	}
 }
+
+func TestInterpolatedDuration(t *testing.T) {
+	type testCase struct {
+		Path   string
+		Env    map[string]string
+		Assert func(t *testing.T, parsed *InterpolatedDuration)
+	}
+
+	testCases := []testCase{
+		{
+			Path: "testdata/environment/interpolated-duration.yml",
+			Env: map[string]string{
+				"MY_DURATION": "30s",
+			},
+			Assert: func(t *testing.T, parsed *InterpolatedDuration) {
+				if e, g := 30*time.Second, parsed; e != time.Duration(*g) {
+					t.Errorf("parsed: expected '%v', got '%v'", e, g)
+				}
+			},
+		},
+	}
+
+	for idx, tc := range testCases {
+		t.Run(fmt.Sprintf("Case #%d", idx), func(t *testing.T) {
+			data, err := os.ReadFile(tc.Path)
+			if err != nil {
+				t.Fatalf("%+v", errors.WithStack(err))
+			}
+
+			if tc.Env != nil {
+				getEnv = func(key string) string {
+					return tc.Env[key]
+				}
+			}
+
+			config := struct {
+				Duration *InterpolatedDuration `yaml:"duration"`
+			}{
+				Duration: NewInterpolatedDuration(-1),
+			}
+
+			if err := yaml.Unmarshal(data, &config); err != nil {
+				t.Fatalf("%+v", errors.WithStack(err))
+			}
+
+			if tc.Assert != nil {
+				tc.Assert(t, config.Duration)
+			}
+		})
+	}
+}