tiny.hypothesis.coverage

1const std = @import("std");23pub const Bucket = enum {4    valid,5    invalid,6    boundary,7    large_state,8};910pub const Counts = struct {11    valid: u64 = 0,12    invalid: u64 = 0,13    boundary: u64 = 0,14    large_state: u64 = 0,1516    pub fn get(self: Counts, bucket: Bucket) u64 {17        return switch (bucket) {18            .valid => self.valid,19            .invalid => self.invalid,20            .boundary => self.boundary,21            .large_state => self.large_state,22        };23    }24};2526pub const Counters = struct {27    counts: Counts = .{},2829    pub fn record(self: *Counters, bucket: Bucket) void {30        const counter = switch (bucket) {31            .valid => &self.counts.valid,32            .invalid => &self.counts.invalid,33            .boundary => &self.counts.boundary,34            .large_state => &self.counts.large_state,35        };36        std.debug.assert(counter.* < std.math.maxInt(u64));37        counter.* += 1;38    }3940    pub fn snapshot(self: *const Counters) Counts {41        return self.counts;42    }4344    pub fn meets(self: *const Counters, minimum: Counts) bool {45        for (std.meta.tags(Bucket)) |bucket| {46            if (self.counts.get(bucket) < minimum.get(bucket)) return false;47        }48        return true;49    }5051    pub fn require(self: *const Counters, minimum: Counts) error{InsufficientCoverage}!void {52        if (!self.meets(minimum)) return error.InsufficientCoverage;53    }54};5556test "coverage: independent generators retain reachability buckets" {57    var plans = Counters{};58    var values = Counters{};59    plans.record(.valid);60    plans.record(.boundary);61    values.record(.invalid);62    values.record(.large_state);6364    try std.testing.expect(plans.meets(.{ .valid = 1, .boundary = 1 }));65    try std.testing.expect(values.meets(.{ .invalid = 1, .large_state = 1 }));66    try std.testing.expect(!plans.meets(.{ .large_state = 1 }));67    try std.testing.expectError(68        error.InsufficientCoverage,69        plans.require(.{ .large_state = 1 }),70    );71    try values.require(.{ .invalid = 1, .large_state = 1 });72    try std.testing.expectEqual(@as(u64, 0), values.snapshot().valid);73}

1pub const coverage = @import("coverage.zig");