fix(bounds): adjust weekly bounds when run on Sunday

The expression -int(date.Weekday()-time.Monday) was used
as an offset from today back to the previous monday.
But since time.Sunday=0, it goes into the next week when
run on Sunday, producing incorrect partitions bounds.

Also add tests for partition.getWeeklyBounds()

Signed-off-by: Daniel Vérité <[email protected]>

Author: dverite

internal/infra/partition/bounds.go

@@ -30,7 +30,12 @@ func getDailyBounds(date time.Time) (lowerBound, upperBound time.Time) {
 }
 
 func getWeeklyBounds(date time.Time) (lowerBound, upperBound time.Time) {
-	lowerBound = time.Date(date.Year(), date.Month(), date.Day(), 0, 0, 0, 0, date.UTC().Location()).AddDate(0, 0, -int(date.Weekday()-time.Monday))
+	offset := int(date.Weekday() - time.Monday)
+	if offset < 0 {
+		offset = 6 // adjust Sunday to be 6 days after Monday instead of 1 day before
+	}
+
+	lowerBound = time.Date(date.Year(), date.Month(), date.Day(), 0, 0, 0, 0, date.UTC().Location()).AddDate(0, 0, -1*offset)
 	upperBound = lowerBound.AddDate(0, 0, nbDaysInAWeek)
 
 	return

internal/infra/partition/bounds_internal_test.go

@@ -0,0 +1,67 @@
+package partition
+
+import (
+	"testing"
+	"time"
+
+	"gotest.tools/assert"
+)
+
+func TestGetWeeklyBounds(t *testing.T) {
+	testCases := []struct {
+		name          string
+		date          time.Time
+		expectedLower time.Time
+		expectedUpper time.Time
+	}{
+		{
+			name:          "Monday",
+			date:          time.Date(2024, 1, 1, 12, 30, 0, 0, time.UTC), // Monday
+			expectedLower: time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC),
+			expectedUpper: time.Date(2024, 1, 8, 0, 0, 0, 0, time.UTC),
+		},
+		{
+			name:          "Wednesday",
+			date:          time.Date(2024, 1, 3, 15, 45, 0, 0, time.UTC), // Wednesday
+			expectedLower: time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC),
+			expectedUpper: time.Date(2024, 1, 8, 0, 0, 0, 0, time.UTC),
+		},
+		{
+			name:          "Sunday",
+			date:          time.Date(2024, 1, 7, 23, 59, 59, 0, time.UTC), // Sunday
+			expectedLower: time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC),
+			expectedUpper: time.Date(2024, 1, 8, 0, 0, 0, 0, time.UTC),
+		},
+		{
+			name:          "Saturday",
+			date:          time.Date(2024, 1, 6, 0, 0, 0, 0, time.UTC), // Saturday
+			expectedLower: time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC),
+			expectedUpper: time.Date(2024, 1, 8, 0, 0, 0, 0, time.UTC),
+		},
+		{
+			name:          "Month boundary",
+			date:          time.Date(2024, 1, 31, 12, 0, 0, 0, time.UTC), // Wednesday
+			expectedLower: time.Date(2024, 1, 29, 0, 0, 0, 0, time.UTC),
+			expectedUpper: time.Date(2024, 2, 5, 0, 0, 0, 0, time.UTC),
+		},
+		{
+			name:          "Year boundary",
+			date:          time.Date(2023, 12, 31, 23, 59, 59, 0, time.UTC), // Sunday
+			expectedLower: time.Date(2023, 12, 25, 0, 0, 0, 0, time.UTC),
+			expectedUpper: time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC),
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			lowerBound, upperBound := getWeeklyBounds(tc.date)
+
+			assert.Equal(t, lowerBound, tc.expectedLower, "Lower bound mismatch")
+			assert.Equal(t, upperBound, tc.expectedUpper, "Upper bound mismatch")
+
+			// Verify the bounds span exactly 7 days
+			daysDiff := upperBound.Sub(lowerBound).Hours() / 24
+			assert.Equal(t, float64(nbDaysInAWeek), daysDiff, "Bounds should span exactly 7 days")
+		})
+	}
+}