Add runtime testing harness

.gitignore

@@ -43,3 +43,5 @@ zig-cache
 
 # Build dir
 bin/*
+*.pyc
+__pycache__

build.zig

@@ -25,7 +25,9 @@ pub fn build(b: *Builder) void {
     var build_path = b.option([]const u8, "build-path", "path to build to") orelse "bin";
     var src_path = b.option([]const u8, "source-path", "path to source") orelse "src";
     var target = b.option([]const u8, "target", "target to build/run for") orelse "x86";
+    const rt_test = b.option(bool, "rt-test", "enable/disable runtime testing") orelse false;
     const builtin_target = if (mem.eql(u8, target, "x86")) builtin.Arch.i386 else unreachable;
+    const zig_path = b.option([]const u8, "zig-path", "the path to the zig binary to use for rt testing") orelse "/snap/bin/zig";
 
     b.makePath(build_path) catch unreachable;
     var grub_path = concat(b.allocator, build_path, "/iso/boot/grub") catch unreachable;
@@ -60,20 +62,25 @@ pub fn build(b: *Builder) void {
     b.default_step.dependOn(link_step);
     for (iso_step.toSlice()) |step| b.default_step.dependOn(step);
 
-    buildRun(b, builtin_target, build_path, iso_path.toSlice(), debug);
+    buildRun(b, builtin_target, build_path, iso_path.toSlice(), debug, rt_test);
     buildDebug(b);
-    buildTest(b, src_path);
+    buildTest(b, src_path, rt_test, target, zig_path);
 }
 
-fn buildTest(b: *Builder, src_path: []const u8) void {
-    const step = b.step("test", "Run all tests");
-    const src_path2 = concat(b.allocator, src_path, "/") catch unreachable;
-    for (src_files.toSlice()) |file| {
-        var file_src = concat(b.allocator, src_path2.toSlice(), file) catch unreachable;
-        file_src.append(".zig") catch unreachable;
-        const tst = b.addTest(file_src.toSlice());
-        tst.setMainPkgPath(".");
-        step.dependOn(&tst.step);
+fn buildTest(b: *Builder, src_path: []const u8, rt_test: bool, target: []const u8, zig_path: []const u8) void {
+    const step = b.step("test", "Run tests");
+    if (rt_test) {
+        const script = b.addSystemCommand([][]const u8{ "python3", "test/rt-test.py", target, zig_path});
+        step.dependOn(&script.step);
+    } else {
+        const src_path2 = concat(b.allocator, src_path, "/") catch unreachable;
+        for (src_files.toSlice()) |file| {
+            var file_src = concat(b.allocator, src_path2.toSlice(), file) catch unreachable;
+            file_src.append(".zig") catch unreachable;
+            const tst = b.addTest(file_src.toSlice());
+            tst.setMainPkgPath(".");
+            step.dependOn(&tst.step);
+        }
     }
 }
 
@@ -89,7 +96,7 @@ fn buildDebug(b: *Builder) void {
     step.dependOn(&cmd.step);
 }
 
-fn buildRun(b: *Builder, target: builtin.Arch, build_path: []const u8, iso_path: []const u8, debug: bool) void {
+fn buildRun(b: *Builder, target: builtin.Arch, build_path: []const u8, iso_path: []const u8, debug: bool, rt_test: bool) void {
     const step = b.step("run", "Run with qemu");
     const qemu = if (target == builtin.Arch.i386) "qemu-system-i386" else unreachable;
     var qemu_flags = ArrayList([]const u8).init(b.allocator);
@@ -107,6 +114,11 @@ fn buildRun(b: *Builder, target: builtin.Arch, build_path: []const u8, iso_path:
             "-s",
             "-S",
         }) catch unreachable;
+    if (rt_test)
+        qemu_flags.appendSlice([][]const u8{
+            "-display",
+            "none"
+        }) catch unreachable;
     const cmd = b.addSystemCommand(qemu_flags.toSlice());
     step.dependOn(&cmd.step);
 }

src/kernel/arch/x86/gdt.zig

@@ -305,4 +305,5 @@ pub fn init() void {
 
     // Load the TSS
     arch.ltr();
+    log.logInfo("Done\n");
 }

src/kernel/arch/x86/idt.zig

@@ -122,4 +122,5 @@ pub fn closeInterruptGate(index: u8) void {
 pub fn init() void {
     log.logInfo("Init idt\n");
     arch.lidt(&idt_ptr);
+    log.logInfo("Done\n");
 }

src/kernel/arch/x86/pit.zig

@@ -273,6 +273,7 @@ pub fn getFrequency() u32 {
 /// Initialise the PIT with a handler to IRQ 0.
 ///
 pub fn init() void {
+    log.logInfo("Init pit\n");
     // Set up counter 0 at 1000hz in a square wave mode counting in binary
     const f: u32 = 10000;
     setupCounter(OCW_SELECT_COUNTER_0, f, OCW_MODE_SQUARE_WAVE_GENERATOR | OCW_BINARY_COUNT_BINARY);
@@ -281,4 +282,5 @@ pub fn init() void {
 
     // Installs 'pitHandler' to IRQ0 (pic.IRQ_PIT)
     irq.registerIrq(pic.IRQ_PIT, pitHandler);
+    log.logInfo("Done\n");
 }

src/kernel/kmain.zig

@@ -32,10 +32,11 @@ pub export fn kmain(mb_info: *multiboot.multiboot_info_t, mb_magic: u32) void {
 
         log.logInfo("Init arch " ++ @tagName(builtin.arch) ++ "\n");
         arch.init(&mem_profile, &fixed_allocator.allocator);
+        log.logInfo("Arch init done\n");
         vga.init();
         tty.init();
 
-        log.logInfo("Finished init\n");
+        log.logInfo("Init done\n");
         tty.print("Hello Pluto from kernel :)\n");
     }
 }

src/kernel/tty.zig

@@ -644,6 +644,7 @@ pub fn init() void {
     printLogo();
     displayPageNumber();
     updateCursor();
+    log.logInfo("Done\n");
 }
 
 fn resetGlobals() void {

test/kernel/arch/x86/rt-test.py

@@ -0,0 +1,6 @@
+def getTestCases(TestCase):
+    return [
+            TestCase("GDT init", [r"Init gdt", r"Done"]),
+            TestCase("IDT init", [r"Init idt", r"Done"]),
+            TestCase("PIT init", [r"Init pit", r".+", "Done"])
+        ]

test/rt-test.py

@@ -0,0 +1,64 @@
+import subprocess
+import signal
+import re
+import sys
+import datetime
+import os
+import importlib.util
+
+class TestCase:
+    def __init__(self, name, expected):
+        self.name = name
+        self.expected = expected
+
+def test_failure(case, exp, expected_idx, found):
+    print("FAILURE: %s #%d, expected '%s', found '%s'" %(case.name, expected_idx + 1, exp, found))
+    sys.exit(1)
+
+def test_pass(case, exp, expected_idx, found):
+    print("PASS: %s #%d, expected '%s', found '%s'" %(case.name, expected_idx + 1, exp, found))
+
+if __name__ == "__main__":
+    arch = sys.argv[1]
+    zig_path = sys.argv[2]
+    spec = importlib.util.spec_from_file_location("arch", "test/kernel/arch/" + arch + "/rt-test.py")
+    arch_module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(arch_module)
+
+    # The list of log statements to look for before arch init is called
+    pre_archinit_cases = [
+            TestCase("Arch init starts", [r"Init arch \w+"])
+        ]
+    # The list of log statements to look for after arch init is called
+    post_archinit_cases = [
+            TestCase("Arch init finishes", [r"Arch init done"]),
+            TestCase("TTY init", [r"Init tty", r"Done"]),
+            TestCase("Init finishes", [r"Init done"])
+        ]
+    # All log statements to look for, including the arch-specific ones
+    cases = pre_archinit_cases + arch_module.getTestCases(TestCase) + post_archinit_cases
+
+    if len(cases) > 0:
+        proc = subprocess.Popen(zig_path + " build run -Drt-test=true", stdout=subprocess.PIPE, shell=True)
+        case_idx = 0
+        # Go through the cases
+        while case_idx < len(cases):
+            case = cases[case_idx]
+            expected_idx = 0
+            # Go through the expected log messages
+            while expected_idx < len(case.expected):
+                e = "\[INFO\] " + case.expected[expected_idx]
+                line = proc.stdout.readline().decode("utf-8")
+                if not line:
+                    break
+                line = line.strip()
+                pattern = re.compile(e)
+                # Pass if the line matches the expected pattern, else fail
+                if pattern.fullmatch(line):
+                    test_pass(case, e, expected_idx, line)
+                else:
+                    test_failure(case, e, expected_idx, line)
+                expected_idx += 1
+            case_idx += 1
+        proc.kill()
+    sys.exit(0)