Add more efficient way to find children of a process

resources/psutil/procfs_test.go

@@ -0,0 +1,41 @@
+package psutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestChildren(t *testing.T) {
+	p := &procfs{
+		children: map[int32][]int32{
+			0: {1},
+			1: {2, 3},
+			2: {4, 5, 6},
+			3: {7, 8, 9},
+		},
+	}
+
+	require.Equal(t, []int32{1}, p.Children(0))
+	require.Equal(t, []int32{2, 3}, p.Children(1))
+	require.Equal(t, []int32{4, 5, 6}, p.Children(2))
+	require.Equal(t, []int32{7, 8, 9}, p.Children(3))
+	require.Equal(t, []int32{}, p.Children(4))
+}
+
+func TestAllChildren(t *testing.T) {
+	p := &procfs{
+		children: map[int32][]int32{
+			0: {1},
+			1: {2, 3},
+			2: {4, 5, 6},
+			3: {7, 8, 9},
+		},
+	}
+
+	require.Equal(t, []int32{1, 2, 3, 4, 5, 6, 7, 8, 9}, p.AllChildren(0))
+	require.Equal(t, []int32{2, 3, 4, 5, 6, 7, 8, 9}, p.AllChildren(1))
+	require.Equal(t, []int32{4, 5, 6}, p.AllChildren(2))
+	require.Equal(t, []int32{7, 8, 9}, p.AllChildren(3))
+	require.Equal(t, []int32{}, p.AllChildren(4))
+}