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package rope
import (
"bytes"
"testing"
"github.com/bruth/assert"
)
var (
small = leaf("x") // small+small is below the leaf concat threshold.
big = leaf("bigger") // A string above the leaf concat threshold.
)
func lowerCoalesceThreshold() func() {
// Temporarily lower auto-coalescing threshold.
thr := concatThreshold
concatThreshold = 3
return func() { concatThreshold = thr }
}
func expectConcat(t *testing.T, n node) *concat {
cc, ok := n.(*concat)
if !ok {
t.Fatalf("concatenation is not *concat: %#v", n)
}
return cc
}
func TestConcSimple(t *testing.T) {
assert.Equal(t, small, conc(emptyNode, small, -1, -1))
assert.Equal(t, small, conc(small, emptyNode, -1, -1))
assert.Equal(t, small+small, conc(small, small, -1, -1))
}
func TestConcNoCoalesce(t *testing.T) {
defer lowerCoalesceThreshold()()
result := conc(big, big, -1, -1)
cc := expectConcat(t, result)
assert.Equal(t, big+big, flatten(cc))
assert.Equal(t, big, cc.Left)
assert.Equal(t, big, cc.Right)
assert.Equal(t, big.length(), cc.Split)
assert.Equal(t, rLenT(big.length()), cc.RLen)
assert.Equal(t, depthT(1), cc.depth())
}
func TestConcCoalesceLeft(t *testing.T) {
defer lowerCoalesceThreshold()()
base := conc(small, big, -1, -1)
_ = expectConcat(t, base)
n := conc(small, base, -1, -1)
cc := expectConcat(t, n)
assert.Equal(t, small+small+big, flatten(cc))
assert.Equal(t, small+small, cc.Left)
assert.Equal(t, big, cc.Right)
assert.Equal(t, 2*small.length(), cc.Split)
assert.Equal(t, rLenT(big.length()), cc.RLen)
assert.Equal(t, depthT(1), cc.depth())
}
func TestConcCoalesceRight(t *testing.T) {
defer lowerCoalesceThreshold()()
base := conc(big, small, -1, -1)
_ = expectConcat(t, base)
n := conc(base, small, -1, -1)
cc := expectConcat(t, n)
assert.Equal(t, big+small+small, flatten(cc))
assert.Equal(t, big, cc.Left)
assert.Equal(t, big.length(), cc.Split)
assert.Equal(t, small+small, cc.Right)
assert.Equal(t, rLenT(2*small.length()), cc.RLen)
assert.Equal(t, depthT(1), cc.depth())
}
func flatten(n node) leaf {
buf := &bytes.Buffer{}
_, _ = n.WriteTo(buf)
return leaf(buf.String())
}
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