move implementation to internal/ directory (#828)

internal/util/circlog/nextpow2int_test.go

@@ -0,0 +1,16 @@
+package circlog
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNextPow2Int(t *testing.T) {
+	require.Equal(t, 512, nextPow2Int(512), "a power of 2 should round to itself")
+	require.Equal(t, 1024, nextPow2Int(513), "should round up to the next power of 2")
+	require.PanicsWithValue(t, "can only round up positive integers", func() { nextPow2Int(0) }, "unimplemented: zero is not positive; corner case")
+	require.PanicsWithValue(t, "can only round up positive integers", func() { nextPow2Int(-1) }, "unimplemented: cannot round up negative numbers")
+	maxInt := int((^uint(0)) >> 1)
+	require.PanicsWithValue(t, "rounded to larger than int()", func() { nextPow2Int(maxInt - 1) }, "cannot round to a number bigger than the int type")
+}