You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tracers_test.go
    path of file: ./repos/go-ethereum/eth/tracers
    
    the code of the file until where you have to start completion: // Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum libra
    
func TestMemCopying(t *testing.T) {
	for i, tc := range []struct {
		memsize  int64
		offset   int64
		size     int64
		wantErr  string
		wantSize int
	}{
		{0, 0, 100, "", 100},    // Should pad up to 100
		{0, 100, 0, "", 0},      // No need to pad (0 size)
		{100, 50, 100, "", 100}, // Should pad 100-150
		{100, 50, 5, "", 5},     // Wanted range fully within memory
		{100, -50, 0, "offset or size must not be negative", 0},                        // Error
		{0, 1, 1024*1024 + 1, "reached limit for padding memory slice: 1048578", 0},    // Error
		{10, 0, 1024*1024 + 100, "reached limit for padding memory slice: 1048666", 0}, // Error

	} {
		mem := vm.NewMemory()
		mem.Resize(uint64(tc.memsize))
		cpy, err := GetMemoryCopyPadded(mem, tc.offset, tc.size)
		if want := tc.wantErr; want != "" {
			if err == nil {
				t.Fatalf("test %d: want '%v' have no error", i, want)
			}
			if have := err.Error(); want != have {
				t.Fatalf("test %d: want '%v' have '%v'", i, want, have)
			}
			continue
		}
		if err != nil {
			t.Fatalf("test %d: unexpected error: %v", i, err)
		}
		if want, have := tc.wantSize, len(cpy); have != want {
			t.Fatalf("test %d: want %v have %v", i, want, have)
		}
	}
}