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@karlseguin
Last active April 19, 2024 00:44
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Custom Zig Test Runner
// in your build.zig, you can specify a custom test runner:
// const tests = b.addTest(.{
// .target = target,
// .optimize = optimize,
// .test_runner = "test_runner.zig", // add this line
// .root_source_file = .{ .path = "src/main.zig" },
// });
const std = @import("std");
const builtin = @import("builtin");
const Allocator = std.mem.Allocator;
const BORDER = "=" ** 80;
// use in custom panic handler
var current_test: ?[]const u8 = null;
pub fn main() !void {
var mem: [4096]u8 = undefined;
var fba = std.heap.FixedBufferAllocator.init(&mem);
const allocator = fba.allocator();
const env = Env.init(allocator);
defer env.deinit(allocator);
var slowest = SlowTracker.init(allocator, 5);
defer slowest.deinit();
var pass: usize = 0;
var fail: usize = 0;
var skip: usize = 0;
var leak: usize = 0;
const printer = Printer.init();
printer.fmt("\r\x1b[0K", .{}); // beginning of line and clear to end of line
for (builtin.test_functions) |t| {
std.testing.allocator_instance = .{};
var status = Status.pass;
slowest.startTiming();
const is_unnamed_test = std.mem.endsWith(u8, t.name, ".test_0");
if (env.filter) |f| {
if (!is_unnamed_test and std.mem.indexOf(u8, t.name, f) == null) {
continue;
}
}
const friendly_name = blk: {
const name = t.name;
var it = std.mem.splitScalar(u8, name, '.');
while (it.next()) |value| {
if (std.mem.eql(u8, value, "test")) {
const rest = it.rest();
break :blk if (rest.len > 0) rest else name;
}
}
break :blk name;
};
current_test = friendly_name;
const result = t.func();
current_test = null;
if (is_unnamed_test) {
continue;
}
const ns_taken = slowest.endTiming(friendly_name);
if (std.testing.allocator_instance.deinit() == .leak) {
leak += 1;
printer.status(.fail, "\n{s}\n\"{s}\" - Memory Leak\n{s}\n", .{BORDER, friendly_name, BORDER});
}
if (result) |_| {
pass += 1;
} else |err| switch (err) {
error.SkipZigTest => {
skip += 1;
status = .skip;
},
else => {
status = .fail;
fail += 1;
printer.status(.fail, "\n{s}\n\"{s}\" - {s}\n{s}\n", .{BORDER, friendly_name, @errorName(err), BORDER});
if (@errorReturnTrace()) |trace| {
std.debug.dumpStackTrace(trace.*);
}
if (env.fail_first) {
break;
}
}
}
if (env.verbose) {
const ms = @as(f64, @floatFromInt(ns_taken)) / 100_000.0;
printer.status(status, "{s} ({d:.2}ms)\n", .{friendly_name, ms});
} else {
printer.status(status, ".", .{});
}
}
const total_tests = pass + fail;
const status = if (fail == 0) Status.pass else Status.fail;
printer.status(status, "\n{d} of {d} test{s} passed\n", .{pass, total_tests, if (total_tests != 1) "s" else ""});
if (skip > 0) {
printer.status(.skip, "{d} test{s} skipped\n", .{skip, if (skip != 1) "s" else ""});
}
if (leak > 0) {
printer.status(.fail, "{d} test{s} leaked\n", .{leak, if (leak != 1) "s" else ""});
}
printer.fmt("\n", .{});
try slowest.display(printer);
printer.fmt("\n", .{});
std.posix.exit(if (fail == 0) 0 else 1);
}
const Printer = struct {
out: std.fs.File.Writer,
fn init() Printer {
return .{
.out = std.io.getStdErr().writer(),
};
}
fn fmt(self: Printer, comptime format: []const u8, args: anytype) void {
std.fmt.format(self.out, format, args) catch unreachable;
}
fn status(self: Printer, s: Status, comptime format: []const u8, args: anytype) void {
const color = switch (s) {
.pass => "\x1b[32m",
.fail => "\x1b[31m",
.skip => "\x1b[33m",
else => "",
};
const out = self.out;
out.writeAll(color) catch @panic("writeAll failed?!");
std.fmt.format(out, format, args) catch @panic("std.fmt.format failed?!");
self.fmt("\x1b[0m", .{});
}
};
const Status = enum {
pass,
fail,
skip,
text,
};
const SlowTracker = struct {
const SlowestQueue = std.PriorityDequeue(TestInfo, void, compareTiming);
max: usize,
slowest: SlowestQueue,
timer: std.time.Timer,
fn init(allocator: Allocator, count: u32) SlowTracker {
const timer = std.time.Timer.start() catch @panic("failed to start timer");
var slowest = SlowestQueue.init(allocator, {});
slowest.ensureTotalCapacity(count) catch @panic("OOM");
return .{
.max = count,
.timer = timer,
.slowest = slowest,
};
}
const TestInfo = struct {
ns: u64,
name: []const u8,
};
fn deinit(self: SlowTracker) void {
self.slowest.deinit();
}
fn startTiming(self: *SlowTracker) void {
self.timer.reset();
}
fn endTiming(self: *SlowTracker, test_name: []const u8) u64 {
var timer = self.timer;
const ns = timer.lap();
var slowest = &self.slowest;
if (slowest.count() < self.max) {
// Capacity is fixed to the # of slow tests we want to track
// If we've tracked fewer tests than this capacity, than always add
slowest.add(TestInfo{ .ns = ns, .name = test_name }) catch @panic("failed to track test timing");
return ns;
}
{
// Optimization to avoid shifting the dequeue for the common case
// where the test isn't one of our slowest.
const fastest_of_the_slow = slowest.peekMin() orelse unreachable;
if (fastest_of_the_slow.ns > ns) {
// the test was faster than our fastest slow test, don't add
return ns;
}
}
// the previous fastest of our slow tests, has been pushed off.
_ = slowest.removeMin();
slowest.add(TestInfo{ .ns = ns, .name = test_name }) catch @panic("failed to track test timing");
return ns;
}
fn display(self: *SlowTracker, printer: Printer) !void {
var slowest = self.slowest;
const count = slowest.count();
printer.fmt("Slowest {d} test{s}: \n", .{count, if (count != 1) "s" else ""});
while (slowest.removeMinOrNull()) |info| {
const ms = @as(f64, @floatFromInt(info.ns)) / 100_000.0;
printer.fmt(" {d:.2}ms\t{s}\n", .{ms, info.name});
}
}
fn compareTiming(context: void, a: TestInfo, b: TestInfo) std.math.Order {
_ = context;
return std.math.order(a.ns, b.ns);
}
};
const Env = struct {
verbose: bool,
fail_first: bool,
filter: ?[]const u8,
fn init(allocator: Allocator) Env {
return .{
.verbose = readEnvBool(allocator, "TEST_VERBOSE", true),
.fail_first = readEnvBool(allocator, "TEST_FAIL_FIRST", false),
.filter = readEnv(allocator, "TEST_FILTER"),
};
}
fn deinit(self: Env, allocator: Allocator) void {
if (self.filter) |f| {
allocator.free(f);
}
}
fn readEnv(allocator: Allocator, key: []const u8) ?[]const u8 {
const v = std.process.getEnvVarOwned(allocator, key) catch |err| {
if (err == error.EnvironmentVariableNotFound) {
return null;
}
std.log.warn("failed to get env var {s} due to err {}", .{key, err});
return null;
};
return v;
}
fn readEnvBool(allocator: Allocator, key: []const u8, deflt: bool) bool {
const value = readEnv(allocator, key) orelse return deflt;
defer allocator.free(value);
return std.ascii.eqlIgnoreCase(value, "true");
}
};
pub fn panic(msg: []const u8, error_return_trace: ?*std.builtin.StackTrace, ret_addr: ?usize) noreturn {
if (current_test) |ct| {
std.debug.print("\x1b[31m{s}\npanic running \"{s}\"\n{s}\x1b[0m\n", .{BORDER, ct, BORDER});
}
std.builtin.default_panic(msg, error_return_trace, ret_addr);
}
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