diff --git a/src/test/java/org/apposed/appose/SharedMemoryTest.java b/src/test/java/org/apposed/appose/SharedMemoryTest.java
index 59b4e6a..05fd7c2 100644
--- a/src/test/java/org/apposed/appose/SharedMemoryTest.java
+++ b/src/test/java/org/apposed/appose/SharedMemoryTest.java
@@ -41,6 +41,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * Tests {@link SharedMemory}.
@@ -54,7 +55,7 @@ public void testShmCreate() throws IOException {
 		int size = 456;
 		try (SharedMemory shm = SharedMemory.create(null, size)) {
 			assertNotNull(shm.name());
-			assertEquals(size, shm.size());
+			assertTrue(shm.size() >= size);
 			assertNotNull(shm.pointer());
 
 			// Modify the memory contents.
@@ -74,8 +75,8 @@ public void testShmCreate() throws IOException {
 			String output = runPython(
 				"from multiprocessing.shared_memory import SharedMemory\n" +
 					"from sys import stdout\n" +
-					"shm = SharedMemory(name='" + shm.name() + "', size=" + shm.size() + ")\n" +
-					"matches = sum(1 for i in range(shm.size) if shm.buf[i] == (shm.size - i) % 256)\n" +
+					"shm = SharedMemory(name='" + shm.name() + "', size=" + size + ")\n" +
+					"matches = sum(1 for i in range(" + size + ") if shm.buf[i] == (" + size + " - i) % 256)\n" +
 					"stdout.write(f'{matches}\\n')\n" +
 					"stdout.flush()\n" +
 					"shm.unlink()\n" // HACK: to satisfy Python's overly aggressive resource tracker
@@ -112,7 +113,7 @@ public void testShmAttach() throws IOException {
 		assertNotNull(shmName);
 		assertFalse(shmName.isEmpty());
 		int shmSize = Integer.parseInt(shmInfo[1]);
-		assertEquals(345, shmSize);
+		assertTrue(shmSize >= 345);
 
 		// Attach to the shared memory and verify it matches expectations.
 		try (SharedMemory shm = SharedMemory.attach(shmName, shmSize)) {
diff --git a/src/test/java/org/apposed/appose/TypesTest.java b/src/test/java/org/apposed/appose/TypesTest.java
index 06e7e39..2d218fe 100644
--- a/src/test/java/org/apposed/appose/TypesTest.java
+++ b/src/test/java/org/apposed/appose/TypesTest.java
@@ -70,7 +70,7 @@ public class TypesTest {
 			"\"shm\":{" +
 				"\"appose_type\":\"shm\"," +
 				"\"name\":\"SHM_NAME\"," +
-				"\"size\":4000" +
+				"\"size\":SHM_SIZE" +
 			"}" +
 		"}" +
 	"}";
@@ -110,7 +110,9 @@ public void testEncode() {
 			data.put("ndArray", ndArray);
 			String json = Types.encode(data);
 			assertNotNull(json);
-			String expected = JSON.replaceAll("SHM_NAME", ndArray.shm().name());
+			String expected = JSON
+				.replaceAll("SHM_NAME", ndArray.shm().name())
+				.replaceAll("SHM_SIZE", "" + ndArray.shm().size());
 			assertEquals(expected, json);
 		}
 	}
@@ -119,11 +121,16 @@ public void testEncode() {
 	public void testDecode() {
 		Map<String, Object> data;
 		String shmName;
+		int shmSize;
 
 		// Create name shared memory segment and decode JSON block.
 		try (SharedMemory shm = SharedMemory.create(null, 4000)) {
 			shmName = shm.name();
-			data = Types.decode(JSON.replaceAll("SHM_NAME", shmName));
+			shmSize = shm.size();
+			String json = JSON
+				.replaceAll("SHM_NAME", shmName)
+				.replaceAll("SHM_SIZE", "" + shmSize);
+			data = Types.decode(json);
 		}
 
 		// Validate results.
@@ -158,7 +165,7 @@ public void testDecode() {
 			assertEquals(20, ndArray.shape().get(1));
 			assertEquals(25, ndArray.shape().get(2));
 			assertEquals(shmName, ndArray.shm().name());
-			assertEquals(4000, ndArray.shm().size());
+			assertEquals(shmSize, ndArray.shm().size());
 		}
 	}