From bdda84dfde2e3c0a20a4949abb0fc485c8fdbee7 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Tue, 27 Oct 2020 19:59:41 -0400
Subject: [PATCH] Adds a very basic shadowing test.

For the record, I'm aware that there's a lot here that I'm not testing. I think the smart move is to get towards a running machine and see which configurations it actually tries to set up, then follow along with appropriate testing; it might cause me to discover a flaw in my comprehension before I've made the same mistake in both the code and a test.
---
 .../Clock SignalTests/IIgsMemoryMapTests.mm   | 43 +++++++++++--------
 1 file changed, 25 insertions(+), 18 deletions(-)

diff --git a/OSBindings/Mac/Clock SignalTests/IIgsMemoryMapTests.mm b/OSBindings/Mac/Clock SignalTests/IIgsMemoryMapTests.mm
index 9d2e4ff79..c13a5048c 100644
--- a/OSBindings/Mac/Clock SignalTests/IIgsMemoryMapTests.mm	
+++ b/OSBindings/Mac/Clock SignalTests/IIgsMemoryMapTests.mm	
@@ -29,36 +29,40 @@ namespace {
 	_memoryMap.set_storage(_ram, _rom);
 }
 
+- (void)write:(uint8_t)value address:(uint32_t)address {
+	const auto &region = MemoryMapRegion(_memoryMap, address);
+	MemoryMapWrite(_memoryMap, region, address, &value);
+}
+
+- (uint8_t)readAddress:(uint32_t)address {
+	const auto &region = MemoryMapRegion(_memoryMap, address);
+	uint8_t value;
+	MemoryMapRead(region, address, &value);
+	return value;
+}
+
 - (void)testHigherRAM {
 	// Fill memory via the map.
 	for(int address = 0x020000; address < 0x800000; ++address) {
-		const auto &region = MemoryMapRegion(_memoryMap, address);
 		const uint8_t value = uint8_t(address ^ (address >> 8));
-		MemoryMapWrite(_memoryMap, region, address, &value);
+		[self write:value address:address];
 	}
 
 	// Test by direct access.
 	for(int address = 0x020000; address < 0x800000; ++address) {
 		const uint8_t value = uint8_t(address ^ (address >> 8));
-		XCTAssertEqual(_ram[address], value);
+		XCTAssertEqual([self readAddress:address], value);
 	}
 }
 
-- (void)testROMReadonly {
+- (void)testROMIsReadonly {
 	_rom[0] = 0xc0;
 
 	// Test that ROM can be read in the correct location.
-	const uint32_t address = 0xfc0000;
-	const auto &region = MemoryMapRegion(_memoryMap, address);
-	uint8_t value;
-	MemoryMapRead(region, address, &value);
-
-	XCTAssertEqual(value, 0xc0);
+	XCTAssertEqual([self readAddress:0xfc0000], 0xc0);
 
 	// Try writing to it, and check that nothing happened.
-	value = 0xfc;
-	MemoryMapWrite(_memoryMap, region, address, &value);
-
+	[self write:0xfc address:0xfc0000];
 	XCTAssertEqual(_rom[0], 0xc0);
 }
 
@@ -66,11 +70,7 @@ namespace {
 	_rom.back() = 0xa8;
 	auto test_bank = [self](uint32_t bank) {
 		const uint32_t address = bank | 0x00ffff;
-		const auto &region = MemoryMapRegion(_memoryMap, address);
-		uint8_t value;
-		MemoryMapRead(region, address, &value);
-		XCTAssertEqual(value, 0xa8);
-
+		XCTAssertEqual([self readAddress:address], 0xa8);
 	};
 
 	test_bank(0x000000);
@@ -79,4 +79,11 @@ namespace {
 	test_bank(0xe10000);
 }
 
+- (void)testShadowing {
+	[self write:0xab address:0x000400];
+	[self write:0xcd address:0x010400];
+	XCTAssertEqual([self readAddress:0xe00400], 0xab);
+	XCTAssertEqual([self readAddress:0xe10400], 0xcd);
+}
+
 @end