Task 352: expand comprehensive test coverage

2 files changed, 10 insertions, 0 deletions

diff --git a/internal/duration/parse.go b/internal/duration/parse.go
index f2febe8..f144ac1 100644
--- a/internal/duration/parse.go
+++ b/internal/duration/parse.go
@@ -11,6 +11,11 @@ import (
 
 var bareIntegerPattern = regexp.MustCompile(`^[+-]?\d+$`)
 
+const (
+	maxInt64 = int64(^uint64(0) >> 1)
+	minInt64 = -maxInt64 - 1
+)
+
 // Parse converts duration text into time.Duration.
 // Go-style durations (e.g. "1h30m") are supported, and bare integers are seconds.
 func Parse(value string) (time.Duration, error) {
@@ -24,6 +29,9 @@ func Parse(value string) (time.Duration, error) {
 		if err != nil {
 			return 0, fmt.Errorf("parse seconds %q: %w", value, err)
 		}
+		if seconds > maxInt64/int64(time.Second) || seconds < minInt64/int64(time.Second) {
+			return 0, fmt.Errorf("duration seconds %q overflows time.Duration", value)
+		}
 		return time.Duration(seconds) * time.Second, nil
 	}
 
diff --git a/internal/duration/parse_test.go b/internal/duration/parse_test.go
index 3b812cd..931f904 100644
--- a/internal/duration/parse_test.go
+++ b/internal/duration/parse_test.go
@@ -63,6 +63,8 @@ func TestParseInvalidDurations(t *testing.T) {
 		"   ",
 		"abc",
 		"1h30x",
+		"9223372036854775807",
+		"-9223372036854775808",
 	}
 
 	for _, input := range tests {