zig/test/cases/error.zig

const assert = @import("std").debug.assert;
const mem = @import("std").mem;

pub fn foo() error!i32 {
    const x = try bar();
    return x + 1;
}

pub fn bar() error!i32 {
    return 13;
}

pub fn baz() error!i32 {
    const y = foo() catch 1234;
    return y + 1;
}

test "error wrapping" {
    assert((baz() catch unreachable) == 15);
}

fn gimmeItBroke() []const u8 {
    return @errorName(error.ItBroke);
}

test "@errorName" {
    assert(mem.eql(u8, @errorName(error.AnError), "AnError"));
    assert(mem.eql(u8, @errorName(error.ALongerErrorName), "ALongerErrorName"));
}


test "error values" {
    const a = i32(error.err1);
    const b = i32(error.err2);
    assert(a != b);
}


test "redefinition of error values allowed" {
    shouldBeNotEqual(error.AnError, error.SecondError);
}
fn shouldBeNotEqual(a: error, b: error) void {
    if (a == b) unreachable;
}


test "error binary operator" {
    const a = errBinaryOperatorG(true) catch 3;
    const b = errBinaryOperatorG(false) catch 3;
    assert(a == 3);
    assert(b == 10);
}
fn errBinaryOperatorG(x: bool) error!isize {
    return if (x) error.ItBroke else isize(10);
}


test "unwrap simple value from error" {
    const i = unwrapSimpleValueFromErrorDo() catch unreachable;
    assert(i == 13);
}
fn unwrapSimpleValueFromErrorDo() error!isize { return 13; }


test "error return in assignment" {
    doErrReturnInAssignment() catch unreachable;
}

fn doErrReturnInAssignment() error!void {
    var x : i32 = undefined;
    x = try makeANonErr();
}

fn makeANonErr() error!i32 {
    return 1;
}