circle radius

pkg/util/map_test.go

@@ -2,11 +2,13 @@ package util_test
 
 import (
 	"fmt"
+	"math"
 	"testing"
 
 	"galaxy/util"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestShortDistance(t *testing.T) {
@@ -54,3 +56,96 @@ func TestNextTravelCoord(t *testing.T) {
 		})
 	}
 }
+
+func TestWrapF(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name  string
+		value float64
+		size  int
+		want  float64
+	}{
+		{
+			name:  "already in range integer",
+			value: 3,
+			size:  10,
+			want:  3,
+		},
+		{
+			name:  "already in range fractional",
+			value: 3.25,
+			size:  10,
+			want:  3.25,
+		},
+		{
+			name:  "positive overflow integer",
+			value: 12,
+			size:  10,
+			want:  2,
+		},
+		{
+			name:  "positive overflow fractional",
+			value: 12.75,
+			size:  10,
+			want:  2.75,
+		},
+		{
+			name:  "negative small fractional",
+			value: -0.25,
+			size:  10,
+			want:  9.75,
+		},
+		{
+			name:  "negative overflow integer",
+			value: -12,
+			size:  10,
+			want:  8,
+		},
+		{
+			name:  "negative overflow fractional",
+			value: -12.75,
+			size:  10,
+			want:  7.25,
+		},
+		{
+			name:  "exact multiple positive",
+			value: 20,
+			size:  10,
+			want:  0,
+		},
+		{
+			name:  "exact multiple negative",
+			value: -20,
+			size:  10,
+			want:  0,
+		},
+		{
+			name:  "size one wraps into [0,1)",
+			value: 123.456,
+			size:  1,
+			want:  math.Mod(123.456, 1),
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := util.WrapF(tt.value, tt.size)
+			require.InDelta(t, tt.want, got, 1e-12)
+			require.GreaterOrEqual(t, got, 0.0)
+			require.Less(t, got, float64(tt.size))
+		})
+	}
+}
+
+// TestWrapF_NaNAndInf verifies IEEE 754 behavior inherited from math.Mod.
+func TestWrapF_NaNAndInf(t *testing.T) {
+	t.Parallel()
+
+	require.True(t, math.IsNaN(util.WrapF(math.NaN(), 10)))
+	require.True(t, math.IsNaN(util.WrapF(math.Inf(1), 10)))
+	require.True(t, math.IsNaN(util.WrapF(math.Inf(-1), 10)))
+}