Add docs and improvement to median filter

pkg/util/math/median.go

@@ -3,7 +3,7 @@
 package math
 
 import (
-	"sort"
+	"slices"
 )
 
 // MedianFilter provides the median value over a rolling window.
@@ -23,6 +23,7 @@ func NewMedianFilter(size int) *MedianFilter {
 	}
 }
 
+// Add adds a value to the filter, sorts the values, and returns the current median.
 func (f *MedianFilter) Add(value float64) float64 {
 	f.values[f.index] = value
 	f.index = (f.index + 1) % len(f.values)
@@ -33,12 +34,11 @@ func (f *MedianFilter) Add(value float64) float64 {
 	}
 
 	copy(f.sorted, f.values)
-	sort.Slice(f.sorted, func(i, j int) bool {
-		return f.sorted[i] < f.sorted[j]
-	})
+	slices.Sort(f.sorted)
 	return f.Median()
 }
 
+// Median returns the current median, else 0 if the filter isn't full yet.
 func (f *MedianFilter) Median() float64 {
 	if f.size < len(f.values)-1 {
 		return 0

pkg/util/math/median_test.go

@@ -9,10 +9,10 @@ import (
 )
 
 func TestMedianFilter(t *testing.T) {
-	t.Run("single value", func(t *testing.T) {
+	t.Run("not full window", func(t *testing.T) {
 		filter := NewMedianFilter(3)
-		result := filter.Add(5.0)
-		assert.Equal(t, 5.0, result)
+		median := filter.Add(5.0)
+		assert.Equal(t, 5.0, median)
 		assert.Equal(t, 0.0, filter.Median())
 	})
 
@@ -29,8 +29,8 @@ func TestMedianFilter(t *testing.T) {
 		filter.Add(1.0)
 		filter.Add(2.0)
 		filter.Add(3.0)
-		result := filter.Add(4.0)
-		assert.Equal(t, 3.0, result)
+		median := filter.Add(4.0)
+		assert.Equal(t, 3.0, median)
 	})
 
 	t.Run("unsorted input", func(t *testing.T) {
@@ -39,7 +39,7 @@ func TestMedianFilter(t *testing.T) {
 		filter.Add(2.0)
 		filter.Add(8.0)
 		filter.Add(1.0)
-		result := filter.Add(9.0)
-		assert.Equal(t, 5.0, result)
+		median := filter.Add(9.0)
+		assert.Equal(t, 5.0, median)
 	})
 }