Add broken error test case

This commit is contained in:
Tim Warren 2015-12-11 14:31:33 -05:00
parent f635b26671
commit 4b413c9e54
4 changed files with 191 additions and 0 deletions

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city-pop/.DS_Store vendored Normal file

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[root]
name = "city-pop"
version = "0.1.0"
dependencies = [
"csv 0.14.3 (registry+https://github.com/rust-lang/crates.io-index)",
"getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
"rustc-serialize 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "byteorder"
version = "0.3.13"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "csv"
version = "0.14.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"byteorder 0.3.13 (registry+https://github.com/rust-lang/crates.io-index)",
"rustc-serialize 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "getopts"
version = "0.2.14"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "rustc-serialize"
version = "0.3.16"
source = "registry+https://github.com/rust-lang/crates.io-index"

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city-pop/Cargo.toml Normal file
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[package]
name = "city-pop"
version = "0.1.0"
authors = ["Tim Warren <twarren@nexient.com>"]
[[bin]]
name = "city-pop"
[dependencies]
csv = "0.*"
rustc-serialize = "0.*"
getopts = "0.*"

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extern crate getopts;
extern crate rustc_serialize;
extern crate csv;
use getopts::Options;
use std::{env, io, fmt, fs, process, str};
use std::path::Path;
use std::error::Error;
// This struct represents the data in each row of the CSV file.
// Type based decoding absolves us of a lot of the nitty gritty error
// handling, like parsing strings as integers or floats
#[derive(Debug, RustcDecodable)]
struct Row {
country: String,
city: String,
accent_city: String,
region: String,
// Not every row has data for the population, latitude or logitude!
// So we express them as `Option` types, which admits the possiblity of
// absence. The CSV parser will fill in the correct value for us.
population: Option<u64>,
latitude: Option<f64>,
longitude: Option<f64>,
}
struct PopulationCount {
city: String,
country: String,
// This is no longer an `Option` because values of this type are only
// constructed if they have a population count.
count: u64,
}
#[derive(Debug)]
enum CliError {
Io(io::Error),
Csv(csv::Error),
NotFound
}
impl fmt::Display for CliError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
CliError::Io(ref err) => err.fmt(f),
CliError::Csv(ref err) => err.fmt(f),
CliError::NotFound => write!(f, "No matching cities with a population were found"),
}
}
}
impl Error for CliError {
fn description(&self) -> &str {
match *self {
CliError::Io(ref err) => err.description(),
CliError::Csv(ref err) => err.description(),
CliError::NotFound => "not found",
}
}
}
impl From<io::Error> for CliError {
fn from(err: io::Error) -> CliError {
CliError::Io(err)
}
}
impl From<csv::Error> for CliError {
fn from(err: csv::Error) -> CliError {
CliError::Csv(err)
}
}
fn print_usage(program: &str, opts: Options) {
println!("{}", opts.usage(&format!("Usage: {} [options] <city>", program)));
}
fn search<P: AsRef<Path>>
(file_path: &Option<P>, city: &str)
-> Result<Vec<PopulationCount>, CliError> {
let mut found = vec![];
let input: Box<io::Read> = match *file_path {
None => Box::new(io::stdin()),
Some(ref file_path) => Box::new(try!(fs::File::open(file_path))),
};
let mut rdr = csv::Reader::from_reader(input);
for row in rdr.decode::<Row>() {
let row = try!(row);
match row.population {
None => {} // Skip it
Some(count) => if row.city == city {
found.push(PopulationCount {
city: row.city,
country: row.country,
count: count,
});
},
}
}
if found.is_empty() {
Err(CliError::NotFound)
} else {
Ok(found)
}
}
fn main() {
let args: Vec<String> = env::args().collect();
let program = args[0].clone();
let mut opts = Options::new();
opts.optopt("f", "file", "Choose an input file instead of using STDIN.", "NAME");
opts.optflag("h", "help", "Show this usage message.");
opts.optflag("q", "quiet", "Silences errors and warnings.");
let matches = match opts.parse(&args[1..]) {
Ok(m) => { m }
Err(e) => { panic!(e.to_string()) }
};
if matches.opt_present("h") {
print_usage(&program, opts);
return;
}
let file = matches.opt_str("f");
let data_file = file.as_ref().map(Path::new);
let city = if !matches.free.is_empty() {
matches.free[0].clone();
} else {
print_usage(&program, opts);
return;
};
match search(&data_file, &city) {
Err(CliError::NotFound) if matches.opt_present("q") => process::exit(1),
Err(err) => panic!("{}", err),
Ok(pops) => for pop in pops {
println!("{}, {}: {:?}", pop.city, pop.country, pop.count);
}
}
}