1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173

use crate::{panic, ByteSliceTestInput, Engine, TargetLocation, Test};
use bolero_generator::driver::DriverMode;
use core::{fmt::Debug, mem::replace};
use rand::{rngs::StdRng, Rng, RngCore, SeedableRng};

/// Test engine implementation using a RNG.
///
/// The inputs will only be derived from the `seed` field.
/// As such, the quality of the inputs may not be high
/// enough to find edge cases.
#[derive(Copy, Clone, PartialEq)]
pub struct RngEngine {
    pub iterations: usize,
    pub max_len: usize,
    pub seed: u64,
    pub driver_mode: Option<DriverMode>,
}

impl Default for RngEngine {
    fn default() -> Self {
        let iterations = get_var("BOLERO_RANDOM_ITERATIONS").unwrap_or(1000);
        let max_len = get_var("BOLERO_RANDOM_MAX_LEN").unwrap_or(4096);
        let seed = get_var("BOLERO_RANDOM_SEED").unwrap_or_else(|| rand::thread_rng().next_u64());

        Self {
            iterations,
            max_len,
            seed,
            driver_mode: None,
        }
    }
}

impl RngEngine {
    /// Create a new `RngEngine`
    pub fn new(location: TargetLocation) -> Self {
        let _ = location;
        Self::default()
    }

    /// Set the number of test iterations
    pub fn with_iterations(self, iterations: usize) -> Self {
        Self {
            iterations,
            max_len: self.max_len,
            seed: self.seed,
            driver_mode: self.driver_mode,
        }
    }

    /// Set the maximum length of a test input
    pub fn with_max_len(self, max_len: usize) -> Self {
        Self {
            iterations: self.iterations,
            max_len,
            seed: self.seed,
            driver_mode: self.driver_mode,
        }
    }

    /// Set the seed for the RNG implementation
    pub fn with_seed(self, seed: u64) -> Self {
        Self {
            iterations: self.iterations,
            max_len: self.max_len,
            seed,
            driver_mode: self.driver_mode,
        }
    }

    /// Set the driver mode for the engine
    pub fn with_driver_mode(self, driver_mode: DriverMode) -> Self {
        Self {
            iterations: self.iterations,
            max_len: self.max_len,
            seed: self.seed,
            driver_mode: Some(driver_mode),
        }
    }
}

impl<T: Test> Engine<T> for RngEngine
where
    T::Value: 'static + Debug + Send,
{
    type Output = ();

    fn set_driver_mode(&mut self, mode: DriverMode) {
        self.driver_mode = Some(mode);
    }

    fn run(self, mut test: T) -> Self::Output {
        panic::set_hook();

        let mut state = RngState::new(self.seed, self.max_len, self.driver_mode);

        let mut valid = 0;
        let mut invalid = 0;
        while valid < self.iterations {
            match test.test(&mut state.next_input()) {
                Ok(true) => {
                    valid += 1;
                    continue;
                }
                Ok(false) => {
                    invalid += 1;
                    if invalid > self.iterations * 2 {
                        panic!(
                            concat!(
                                "Test input could not be satisfied after {} iterations:\n",
                                "         valid: {}\n",
                                "       invalid: {}\n",
                                "  target count: {}\n",
                                "\n",
                                "Try reconfiguring the input generator to produce more valid inputs",
                            ),
                            valid + invalid,
                            valid,
                            invalid,
                            self.iterations
                        );
                    }
                    continue;
                }
                Err(_) => {
                    let failure = test
                        .shrink(
                            replace(&mut state.buffer, vec![]),
                            Some(self.seed),
                            Some(state.driver_mode),
                        )
                        .expect("test should fail");

                    eprintln!("{}", failure);

                    std::panic::resume_unwind(Box::new(failure));
                }
            }
        }
    }
}

struct RngState {
    rng: StdRng,
    max_len: usize,
    driver_mode: DriverMode,
    buffer: Vec<u8>,
}

impl RngState {
    fn new(seed: u64, max_len: usize, driver_mode: Option<DriverMode>) -> Self {
        Self {
            rng: StdRng::seed_from_u64(seed),
            max_len,
            driver_mode: driver_mode.unwrap_or(DriverMode::Forced),
            buffer: vec![],
        }
    }

    fn next_input(&mut self) -> ByteSliceTestInput {
        let len = self.rng.gen_range(0, self.max_len);
        self.buffer.clear();
        self.buffer.resize(len, 0);
        self.rng.fill_bytes(&mut self.buffer);
        ByteSliceTestInput::new(&self.buffer, Some(self.driver_mode))
    }
}

fn get_var<T: std::str::FromStr>(name: &str) -> Option<T> {
    std::env::var(name)
        .ok()
        .and_then(|value| value.parse::<T>().ok())
}