diff --git a/internal/history/main.go b/internal/history/main.go
index 8b4246b..0a13656 100644
--- a/internal/history/main.go
+++ b/internal/history/main.go
@@ -111,52 +111,3 @@ func (h *history) Log(method, query, answer string) error {
 	}
 	return nil
 }
-
-func augmentHistoryQuery(hq *HistoryQuery) error {
-
-	if after, err := strToTime(hq.AfterStr); err == nil {
-		hq.After = after
-	}
-
-	if before, err := strToTime(hq.BeforeStr); err == nil {
-		hq.Before = before
-	}
-
-	return nil
-}
-
-func strToTime(input string) (*time.Time, error) {
-	var layout string
-	if len(input) == 4 {
-		// Input is a year, convert to YYYY-01-01
-		layout = "2006"
-		input += "-01-01"
-	} else if len(input) == 10 {
-		// Input is already in YYYY-MM-DD format
-		layout = "2006-01-02"
-	} else if len(input) == 8 {
-		// Input is in HH:MM:SS format, that's today
-		layout = time.TimeOnly
-	} else if len(input) == len("2006-01-02T15:04:05") {
-		// Input is in RFC3339 format without time zone (local)
-		layout = "2006-01-02T15:04:05"
-	} else if len(input) == len(time.RFC3339) {
-		// Input is in RFC3339 format
-		layout = time.RFC3339
-	} else {
-		return nil, fmt.Errorf("invalid date format: %s", input)
-	}
-
-	t, err := time.Parse(layout, input)
-	if err != nil {
-		return nil, fmt.Errorf("failed to parse date: %w", err)
-	}
-
-	// If the input was in TimeOnly format, set the date to today
-	if layout == time.TimeOnly {
-		now := time.Now()
-		t = time.Date(now.Year(), now.Month(), now.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(), t.Location())
-	}
-
-	return &t, nil
-}
diff --git a/internal/history/utils.go b/internal/history/utils.go
new file mode 100644
index 0000000..c95dd60
--- /dev/null
+++ b/internal/history/utils.go
@@ -0,0 +1,54 @@
+package history
+
+import (
+	"fmt"
+	"time"
+)
+
+func augmentHistoryQuery(hq *HistoryQuery) error {
+	if after, err := strToTime(hq.AfterStr); err == nil {
+		hq.After = after
+	}
+
+	if before, err := strToTime(hq.BeforeStr); err == nil {
+		hq.Before = before
+	}
+
+	return nil
+}
+
+func strToTime(input string) (*time.Time, error) {
+	var layout string
+	if len(input) == 4 {
+		// Input is a year, convert to YYYY-01-01
+		layout = "2006-01-01"
+		input += "-01-01"
+	} else if len(input) == 10 {
+		// Input is already in YYYY-MM-DD format
+		layout = "2006-01-02"
+	} else if len(input) == 8 {
+		// Input is in HH:MM:SS format, that's today
+		layout = time.TimeOnly
+	} else if len(input) == len("2006-01-02T15:04:05") {
+		// Input is in RFC3339 format without time zone (local)
+		layout = "2006-01-02T15:04:05"
+	} else if len(input) == len(time.RFC3339) {
+		// Input is in RFC3339 format
+		layout = time.RFC3339
+	} else {
+		return nil, fmt.Errorf("invalid date format: %s", input)
+	}
+
+	t, err := time.Parse(layout, input)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse date: %w", err)
+	}
+
+	// If the input was in TimeOnly format, set the date to today
+	if layout == time.TimeOnly {
+		now := time.Now()
+		t = time.Date(now.Year(), now.Month(), now.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(), t.Location())
+	}
+
+	return &t, nil
+}
diff --git a/internal/history/utils_test.go b/internal/history/utils_test.go
new file mode 100644
index 0000000..b43f478
--- /dev/null
+++ b/internal/history/utils_test.go
@@ -0,0 +1,79 @@
+package history
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func timePtr(t time.Time) *time.Time {
+	return &t
+}
+
+func TestAugmentHistoryQuery(t *testing.T) {
+	cheatingAfter := time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC)
+	cheatingBefore := time.Date(2025, 1, 1, 0, 0, 0, 0, time.UTC)
+
+	tests := []struct {
+		afterStr  string
+		beforeStr string
+		after     *time.Time
+		before    *time.Time
+	}{
+		{"2024", "2025", &cheatingAfter, &cheatingBefore},
+		{"2024", "", &cheatingAfter, nil},
+		{"", "2025", nil, &cheatingBefore},
+		{"invalid", "invalid", nil, nil},
+		{"", "", nil, nil},
+	}
+
+	for _, test := range tests {
+		t.Run(test.afterStr, func(t *testing.T) {
+			hq := &HistoryQuery{
+				AfterStr:  test.afterStr,
+				BeforeStr: test.beforeStr,
+			}
+			err := augmentHistoryQuery(hq)
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+			assert.Equal(t, test.after, hq.After)
+			assert.Equal(t, test.before, hq.Before)
+		})
+	}
+}
+
+func TestStrToTime(t *testing.T) {
+	nowTime := time.Now()
+	tests := []struct {
+		input    string
+		expected *time.Time
+	}{
+		{"2024", timePtr(time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC))},
+		{"2024-01-01", timePtr(time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC))},
+		{"12:34:56", timePtr(time.Date(time.Now().Year(), time.Now().Month(), time.Now().Day(), 12, 34, 56, 0, time.UTC))},
+		{"2024-01-01T12:34:56", timePtr(time.Date(2024, 1, 1, 12, 34, 56, 0, time.UTC))},
+		{nowTime.Format(time.RFC3339), timePtr(time.Date(nowTime.Year(), nowTime.Month(), nowTime.Day(), nowTime.Hour(), nowTime.Minute(), nowTime.Second(), 0, nowTime.Location()))},
+		{"invalid", nil},
+	}
+
+	for _, test := range tests {
+		t.Run(test.input, func(t *testing.T) {
+			actual, err := strToTime(test.input)
+			if err != nil {
+				if test.expected != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+				return
+			}
+			if actual == nil {
+				t.Error("expected time, got nil")
+				return
+			}
+
+			assert.Equal(t, test.expected, actual)
+		})
+	}
+
+}