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| 1 | +'use strict'; |
| 2 | + |
| 3 | +// Tests that histograms can record a value of zero. |
| 4 | + |
| 5 | +require('../common'); |
| 6 | +const assert = require('assert'); |
| 7 | +const { |
| 8 | + createHistogram, |
| 9 | + createSlidingWindowHistogram, |
| 10 | + importHistogram, |
| 11 | +} = require('perf_hooks'); |
| 12 | + |
| 13 | +{ |
| 14 | + const h = createHistogram(); |
| 15 | + h.record(0); |
| 16 | + h.record(-0); |
| 17 | + h.record(0n); |
| 18 | + |
| 19 | + assert.strictEqual(h.count, 3); |
| 20 | + assert.strictEqual(h.exceeds, 0); |
| 21 | + assert.strictEqual(h.min, 0); |
| 22 | + assert.strictEqual(h.minBigInt, 0n); |
| 23 | + assert.strictEqual(h.max, 0); |
| 24 | + assert.strictEqual(h.maxBigInt, 0n); |
| 25 | + assert.strictEqual(h.mean, 0); |
| 26 | + assert.strictEqual(h.stddev, 0); |
| 27 | + assert.strictEqual(h.percentile(50), 0); |
| 28 | + assert.strictEqual(h.percentileBigInt(100), 0n); |
| 29 | + assert.deepStrictEqual(h.percentiles, new Map([[0, 0], [100, 0]])); |
| 30 | +} |
| 31 | + |
| 32 | +{ |
| 33 | + const h = createHistogram(); |
| 34 | + h.record(5); |
| 35 | + // A zero recorded after a non-zero value becomes the minimum. |
| 36 | + h.record(0); |
| 37 | + h.record(0); |
| 38 | + h.record(3); |
| 39 | + |
| 40 | + assert.strictEqual(h.count, 4); |
| 41 | + assert.strictEqual(h.min, 0); |
| 42 | + assert.strictEqual(h.max, 5); |
| 43 | + assert.strictEqual(h.mean, 2); |
| 44 | + assert.strictEqual(h.countAt(0), 2); |
| 45 | + assert.strictEqual(h.cdf(0), 0.5); |
| 46 | + assert.strictEqual(h.percentile(50), 0); |
| 47 | + assert.strictEqual(h.percentile(75), 3); |
| 48 | +} |
| 49 | + |
| 50 | +{ |
| 51 | + const h = createHistogram(); |
| 52 | + for (const value of [-1, -1n, Number.MIN_SAFE_INTEGER, -(2n ** 63n)]) { |
| 53 | + assert.throws(() => h.record(value), { code: 'ERR_OUT_OF_RANGE' }); |
| 54 | + } |
| 55 | + assert.strictEqual(h.count, 0); |
| 56 | +} |
| 57 | + |
| 58 | +{ |
| 59 | + const h = createHistogram(); |
| 60 | + h.recordCorrected(0, 10); |
| 61 | + h.recordCorrected(0n, 10n); |
| 62 | + |
| 63 | + assert.strictEqual(h.count, 2); |
| 64 | + assert.strictEqual(h.min, 0); |
| 65 | + assert.strictEqual(h.max, 0); |
| 66 | + |
| 67 | + for (const args of [[-1, 10], [-1n, 10n], [0, 0], [0n, 0n]]) { |
| 68 | + assert.throws(() => h.recordCorrected(...args), |
| 69 | + { code: 'ERR_OUT_OF_RANGE' }); |
| 70 | + } |
| 71 | + assert.strictEqual(h.count, 2); |
| 72 | +} |
| 73 | + |
| 74 | +{ |
| 75 | + const a = createHistogram(); |
| 76 | + a.record(0); |
| 77 | + a.record(0); |
| 78 | + a.record(7); |
| 79 | + |
| 80 | + const b = createHistogram(); |
| 81 | + b.add(a); |
| 82 | + assert.strictEqual(b.count, 3); |
| 83 | + assert.strictEqual(b.min, 0); |
| 84 | + assert.strictEqual(b.max, 7); |
| 85 | + assert.strictEqual(b.countAt(0), 2); |
| 86 | + |
| 87 | + const zero = createHistogram(); |
| 88 | + zero.record(0); |
| 89 | + |
| 90 | + b.subtract(zero); |
| 91 | + assert.strictEqual(b.count, 2); |
| 92 | + assert.strictEqual(b.min, 0); |
| 93 | + assert.strictEqual(b.countAt(0), 1); |
| 94 | + |
| 95 | + b.subtract(zero); |
| 96 | + assert.strictEqual(b.count, 1); |
| 97 | + assert.strictEqual(b.min, 7); |
| 98 | + assert.strictEqual(b.countAt(0), 0); |
| 99 | +} |
| 100 | + |
| 101 | +for (const values of [[0], [0, 0, 7]]) { |
| 102 | + const h = createHistogram(); |
| 103 | + for (const value of values) h.record(value); |
| 104 | + |
| 105 | + const imported = importHistogram(h.export()); |
| 106 | + assert.strictEqual(imported.count, values.length); |
| 107 | + assert.strictEqual(imported.min, 0); |
| 108 | + assert.strictEqual(imported.max, h.max); |
| 109 | + assert.strictEqual(imported.countAt(0), h.countAt(0)); |
| 110 | + assert.deepStrictEqual(imported.percentiles, h.percentiles); |
| 111 | +} |
| 112 | + |
| 113 | +{ |
| 114 | + // Values smaller than `lowest`, including zero, might not be distinguishable |
| 115 | + // from each other. |
| 116 | + const h = createHistogram({ lowest: 1000 }); |
| 117 | + h.record(0); |
| 118 | + h.record(1); |
| 119 | + |
| 120 | + assert.strictEqual(h.count, 2); |
| 121 | + assert.strictEqual(h.min, 0); |
| 122 | + assert.strictEqual(h.countAt(0), 2); |
| 123 | +} |
| 124 | + |
| 125 | +{ |
| 126 | + const histogram = createSlidingWindowHistogram({ |
| 127 | + chunks: 2, |
| 128 | + recordsPerChunk: 2, |
| 129 | + }); |
| 130 | + histogram.record(0); |
| 131 | + histogram.record(0n); |
| 132 | + histogram.record(3); |
| 133 | + |
| 134 | + const snapshot = histogram.snapshot(); |
| 135 | + assert.strictEqual(snapshot.count, 3); |
| 136 | + assert.strictEqual(snapshot.min, 0); |
| 137 | + assert.strictEqual(snapshot.max, 3); |
| 138 | + assert.strictEqual(snapshot.countAt(0), 2); |
| 139 | + |
| 140 | + for (const value of [-1, -1n]) { |
| 141 | + assert.throws(() => histogram.record(value), { code: 'ERR_OUT_OF_RANGE' }); |
| 142 | + } |
| 143 | + assert.strictEqual(histogram.snapshot().count, 3); |
| 144 | +} |
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