Simulator is just about ready for real-world testing now. Added a simulated

MOS6551 ACIA at address $C000 which does buffered input and output via the
console. Updated the README with a bit more documentation, and bumped the
version number to 0.1 because I'm impatient.

src/test/java/com/loomcom/symon/AciaTest.java

@@ -0,0 +1,122 @@
+package com.loomcom.symon;
+
+import org.junit.*;
+
+import com.loomcom.symon.devices.Acia;
+import com.loomcom.symon.exceptions.FifoUnderrunException;
+
+import static org.junit.Assert.*;
+
+public class AciaTest {
+
+  @Test
+  public void newAciaShouldHaveTxEmptyStatus() throws Exception {
+    Acia acia = new Acia(0x000);
+
+    assertEquals(0x10, acia.read(0x0001));
+  }
+
+  @Test
+  public void aciaShouldHaveTxEmptyStatusOffIfTxHasData() throws Exception {
+    Acia acia = new Acia(0x000);
+
+    acia.txWrite('a');
+    assertEquals(0x00, acia.read(0x0001));
+  }
+
+  @Test
+  public void aciaShouldHaveRxFullStatusOffIfRxHasData() throws Exception {
+    Acia acia = new Acia(0x000);
+
+    acia.rxWrite('a');
+    assertEquals(0x18, acia.read(0x0001));
+  }
+
+  @Test
+  public void aciaShouldHaveTxEmptyAndRxFullStatusOffIfRxAndTxHaveData()
+      throws Exception {
+    Acia acia = new Acia(0x000);
+
+    acia.rxWrite('a');
+    acia.txWrite('b');
+
+    assertEquals(0x08, acia.read(0x0001));
+  }
+
+  @Test
+  public void readingBuffersUntilEmptyShouldResetStatus()
+      throws Exception {
+    Acia acia = new Acia(0x0000);
+
+    acia.rxWrite('a');
+    acia.txWrite('b');
+
+    assertEquals(0x08, acia.read(0x0001));
+
+    assertEquals('a', acia.rxRead());
+    assertEquals('b', acia.txRead());
+
+    assertEquals(0x10, acia.read(0x0001));
+  }
+
+  @Test
+  public void readingPastEmptyRxBufferShouldThrowException()
+    throws Exception {
+    Acia acia = new Acia(0x0000);
+
+    acia.rxWrite('a');
+    assertEquals(0x18, acia.read(0x0001)); // not empty
+
+    assertEquals('a', acia.rxRead());
+    assertEquals(0x10, acia.read(0x0001)); // becomes empty
+
+    // Should raise (note: I prefer this style to @Test(expected=...)
+    // because it allows much finer grained control over asserting
+    // exactly where the exception is expected to be raised.)
+    try {
+      // Should cause an underrun
+      acia.rxRead();
+      fail("Should have raised FifoUnderrunException.");
+    } catch (FifoUnderrunException ex) {}
+
+    assertEquals(0x10, acia.read(0x0001)); // still again
+
+    for (int i = 0; i < Acia.BUF_LEN; i++) {
+      acia.rxWrite('a');
+    }
+
+    // Should NOT cause an overrun
+    acia.rxWrite('a'); // nothing thrown
+  }
+
+  @Test
+  public void readingPastEmptyTxBufferShouldThrowException()
+    throws Exception {
+    Acia acia = new Acia(0x0000);
+
+    acia.txWrite('a');
+    assertEquals(0x00, acia.read(0x0001)); // not empty
+
+    assertEquals('a', acia.txRead());
+    assertEquals(0x10, acia.read(0x0001)); // becomes empty
+
+    // Should raise (note: I prefer this style to @Test(expected=...)
+    // because it allows much finer grained control over asserting
+    // exactly where the exception is expected to be raised.)
+    try {
+      // Should cause an underrun
+      acia.txRead();
+      fail("Should have raised FifoUnderrunException.");
+    } catch (FifoUnderrunException ex) {}
+
+    assertEquals(0x10, acia.read(0x0001)); // still empty
+
+    for (int i = 0; i < Acia.BUF_LEN; i++) {
+      acia.txWrite('a');
+    }
+
+    // Should NOT cause an overrun
+    acia.txWrite('a'); // Nothing thrown.
+  }
+
+}

src/test/java/com/loomcom/symon/CpuIndirectIndexedModeTest.java

@@ -1,7 +1,6 @@
 package com.loomcom.symon;
 
 import com.loomcom.symon.devices.Memory;
-import com.loomcom.symon.exceptions.MemoryAccessException;
 
 import org.junit.*;
 import static org.junit.Assert.*;