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package generic_test
// This is package generic_test in order to get around an import cycle: this
// package imports teststat to do its testing, but package teststat imports
// generic to use its Histogram in the Quantiles helper function.
import (
"go/ast"
"go/importer"
"go/parser"
"go/token"
"go/types"
"io/ioutil"
"math"
"math/rand"
"sync"
"testing"
"github.com/go-kit/kit/metrics/generic"
"github.com/go-kit/kit/metrics/teststat"
)
func TestCounter(t *testing.T) {
name := "my_counter"
counter := generic.NewCounter(name).With("label", "counter").(*generic.Counter)
if want, have := name, counter.Name; want != have {
t.Errorf("Name: want %q, have %q", want, have)
}
value := counter.Value
if err := teststat.TestCounter(counter, value); err != nil {
t.Fatal(err)
}
}
func TestValueReset(t *testing.T) {
counter := generic.NewCounter("test_value_reset")
counter.Add(123)
counter.Add(456)
counter.Add(789)
if want, have := float64(123+456+789), counter.ValueReset(); want != have {
t.Errorf("want %f, have %f", want, have)
}
if want, have := float64(0), counter.Value(); want != have {
t.Errorf("want %f, have %f", want, have)
}
}
func TestGauge(t *testing.T) {
name := "my_gauge"
gauge := generic.NewGauge(name).With("label", "gauge").(*generic.Gauge)
if want, have := name, gauge.Name; want != have {
t.Errorf("Name: want %q, have %q", want, have)
}
value := func() []float64 { return []float64{gauge.Value()} }
if err := teststat.TestGauge(gauge, value); err != nil {
t.Fatal(err)
}
}
func TestHistogram(t *testing.T) {
name := "my_histogram"
histogram := generic.NewHistogram(name, 50).With("label", "histogram").(*generic.Histogram)
if want, have := name, histogram.Name; want != have {
t.Errorf("Name: want %q, have %q", want, have)
}
quantiles := func() (float64, float64, float64, float64) {
return histogram.Quantile(0.50), histogram.Quantile(0.90), histogram.Quantile(0.95), histogram.Quantile(0.99)
}
if err := teststat.TestHistogram(histogram, quantiles, 0.01); err != nil {
t.Fatal(err)
}
}
func TestIssue424(t *testing.T) {
var (
histogram = generic.NewHistogram("dont_panic", 50)
concurrency = 100
operations = 1000
wg sync.WaitGroup
)
wg.Add(concurrency)
for i := 0; i < concurrency; i++ {
go func() {
defer wg.Done()
for j := 0; j < operations; j++ {
histogram.Observe(float64(j))
histogram.Observe(histogram.Quantile(0.5))
}
}()
}
wg.Wait()
}
func TestSimpleHistogram(t *testing.T) {
histogram := generic.NewSimpleHistogram().With("label", "simple_histogram").(*generic.SimpleHistogram)
var (
sum int
count = 1234 // not too big
)
for i := 0; i < count; i++ {
value := rand.Intn(1000)
sum += value
histogram.Observe(float64(value))
}
var (
want = float64(sum) / float64(count)
have = histogram.ApproximateMovingAverage()
tolerance = 0.001 // real real slim
)
if math.Abs(want-have)/want > tolerance {
t.Errorf("want %f, have %f", want, have)
}
}
// Naive atomic alignment test.
// The problem is related to the use of `atomic.*` and not directly to a structure.
// But currently works for Counter and Gauge.
// To have a more solid test, this test should be removed and the other tests should be run on a 32-bit arch.
func TestAtomicAlignment(t *testing.T) {
content, err := ioutil.ReadFile("./generic.go")
if err != nil {
t.Fatal(err)
}
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "generic.go", content, parser.ParseComments)
if err != nil {
t.Fatal(err)
}
conf := types.Config{Importer: importer.ForCompiler(fset, "source", nil)}
pkg, err := conf.Check(".", fset, []*ast.File{file}, nil)
if err != nil {
t.Fatal(err)
}
// uses ARM as reference for 32-bit arch
sizes := types.SizesFor("gc", "arm")
names := []string{"Counter", "Gauge"}
for _, name := range names {
t.Run(name, func(t *testing.T) {
checkAtomicAlignment(t, sizes, pkg.Scope().Lookup(name), pkg)
})
}
}
func checkAtomicAlignment(t *testing.T, sizes types.Sizes, obj types.Object, pkg *types.Package) {
t.Helper()
st := obj.Type().Underlying().(*types.Struct)
posToCheck := make(map[int]types.Type)
var vars []*types.Var
for i := 0; i < st.NumFields(); i++ {
field := st.Field(i)
if v, ok := field.Type().(*types.Basic); ok {
switch v.Kind() {
case types.Uint64, types.Float64, types.Int64:
posToCheck[i] = v
}
}
vars = append(vars, types.NewVar(field.Pos(), pkg, field.Name(), field.Type()))
}
offsets := sizes.Offsetsof(vars)
for i, offset := range offsets {
if _, ok := posToCheck[i]; !ok {
continue
}
if offset%8 != 0 {
t.Errorf("misalignment detected in %s for the type %s, offset %d", obj.Name(), posToCheck[i], offset)
}
}
}
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