util.dbuffer: Add efficient shortcuts for discard() in certain cases
If the buffer is already empty, nothing to do. If we're throwing away the
whole buffer, we can just empty it and avoid read_chunk() (which in turn
may collapse()). These shortcuts are much more efficient.
describe("parse", function()
local parse
setup(function() parse = require"util.argparse".parse; end);
it("works", function()
-- basic smoke test
local opts = parse({ "--help" });
assert.same({ help = true }, opts);
end);
it("returns if no args", function() assert.same({}, parse({})); end);
it("supports boolean flags", function()
local opts, err = parse({ "--foo"; "--no-bar" });
assert.falsy(err);
assert.same({ foo = true; bar = false }, opts);
end);
it("consumes input until the first argument", function()
local arg = { "--foo"; "bar"; "--baz" };
local opts, err = parse(arg);
assert.falsy(err);
assert.same({ foo = true, "bar", "--baz" }, opts);
assert.same({ "bar"; "--baz" }, arg);
end);
it("expands short options", function()
local opts, err = parse({ "--foo"; "-b" }, { short_params = { b = "bar" } });
assert.falsy(err);
assert.same({ foo = true; bar = true }, opts);
end);
it("supports value arguments", function()
local opts, err = parse({ "--foo"; "bar"; "--baz=moo" }, { value_params = { foo = true; bar = true } });
assert.falsy(err);
assert.same({ foo = "bar"; baz = "moo" }, opts);
end);
it("demands values for value params", function()
local opts, err, where = parse({ "--foo" }, { value_params = { foo = true } });
assert.falsy(opts);
assert.equal("missing-value", err);
assert.equal("--foo", where);
end);
it("reports where the problem is", function()
local opts, err, where = parse({ "-h" });
assert.falsy(opts);
assert.equal("param-not-found", err);
assert.equal("-h", where, "returned where");
end);
end);