diff --git a/metropolis/pkg/gpt/structs_test.go b/metropolis/pkg/gpt/structs_test.go
new file mode 100644
index 0000000..dc53635
--- /dev/null
+++ b/metropolis/pkg/gpt/structs_test.go
@@ -0,0 +1,27 @@
+package gpt
+
+import (
+	"encoding/binary"
+	"reflect"
+	"testing"
+)
+
+func TestStructureSizes(t *testing.T) {
+	cases := []struct {
+		StructInstance interface{}
+		ExpectedSize   int
+	}{
+		{mbr{}, 512},
+		{mbrPartitionRecord{}, 16},
+		{header{}, 92},
+		{partition{}, 128},
+	}
+	for _, c := range cases {
+		t.Run(reflect.TypeOf(c.StructInstance).String(), func(t *testing.T) {
+			actualSize := binary.Size(c.StructInstance)
+			if actualSize != c.ExpectedSize {
+				t.Errorf("Expected %d bytes, got %d", c.ExpectedSize, actualSize)
+			}
+		})
+	}
+}