I'm trying to implement a very simple test function to verify results coming from my solutions for Euler problems.
In the following code I've created a map of slices where on the index 0, I call the function which return a integer and on the index 1, the result I expect from that function.
package euler
import "testing"
func TestEulers(t *testing.T) {
tests := map[string][]int{
"Euler1": {Euler1(), 233168},
"Euler2": {Euler2(), 4613732},
"Euler3": {Euler3(), 6857},
"Euler4": {Euler4(), 906609},
"Euler5": {Euler5(), 232792560},
"Euler6": {Euler6(), 25164150},
}
for key, value := range tests {
if value[0] != value[1] {
t.Errorf("%s
Expected: %d
Got:%d",
key, value[0], value[1])
}
}
}
For that map, every function works fine and return the result I expect if I run one by one or if I comment, let's say, half part of those keys/values.
For example, if I call the the function above with these lines commented the test will PASS.
tests := map[string][]int{
"Euler1": {Euler1(), 233168},
// "Euler2": {Euler2(), 4613732},
"Euler3": {Euler3(), 6857},
"Euler4": {Euler4(), 906609},
// "Euler5": {Euler5(), 232792560},
// "Euler6": {Euler6(), 25164150},
}
But if I arrange the comments on that next way, for example, the test wouldn't.
tests := map[string][]int{
//"Euler1": {Euler1(), 233168},
"Euler2": {Euler2(), 4613732},
"Euler3": {Euler3(), 6857},
"Euler4": {Euler4(), 906609},
//"Euler5": {Euler5(), 232792560},
// "Euler6": {Euler6(), 25164150},
}
The test will give me an error:
WARNING: DATA RACE
Write by goroutine 6:
runtime.closechan()
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/runtime/chan.go:295 +0x0
github.com/alesr/project-euler.Euler2()
/Users/Alessandro/GO/src/github.com/alesr/project-euler/euler.go:40 +0xd7
github.com/alesr/project-euler.TestEulers()
/Users/Alessandro/GO/src/github.com/alesr/project-euler/euler_test.go:9 +0x46
testing.tRunner()
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/testing/testing.go:456 +0xdc
Previous read by goroutine 7:
runtime.chansend()
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/runtime/chan.go:107 +0x0
github.com/alesr/numbers.FibonacciGen.func1()
/Users/Alessandro/GO/src/github.com/alesr/numbers/numbers.go:103 +0x59
Goroutine 6 (running) created at:
testing.RunTests()
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/testing/testing.go:561 +0xaa3
testing.(*M).Run()
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/testing/testing.go:494 +0xe4
main.main()
github.com/alesr/project-euler/_test/_testmain.go:54 +0x20f
Goroutine 7 (running) created at:
github.com/alesr/numbers.FibonacciGen()
/Users/Alessandro/GO/src/github.com/alesr/numbers/numbers.go:105 +0x60
github.com/alesr/project-euler.Euler2()
/Users/Alessandro/GO/src/github.com/alesr/project-euler/euler.go:27 +0x32
github.com/alesr/project-euler.TestEulers()
/Users/Alessandro/GO/src/github.com/alesr/project-euler/euler_test.go:9 +0x46
testing.tRunner()
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/testing/testing.go:456 +0xdc
==================
panic: send on closed channel
goroutine 36 [running]:
github.com/alesr/numbers.FibonacciGen.func1(0xc8200a01e0)
/Users/Alessandro/GO/src/github.com/alesr/numbers/numbers.go:103 +0x5a
created by github.com/alesr/numbers.FibonacciGen
/Users/Alessandro/GO/src/github.com/alesr/numbers/numbers.go:105 +0x61
goroutine 1 [chan receive]:
testing.RunTests(0x24d038, 0x2f7340, 0x1, 0x1, 0xf78401)
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/testing/testing.go:562 +0xafa
testing.(*M).Run(0xc82004df00, 0x1ff0e8)
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/testing/testing.go:494 +0xe5
main.main()
github.com/alesr/project-euler/_test/_testmain.go:54 +0x210
goroutine 17 [syscall, locked to thread]:
runtime.goexit()
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/runtime/asm_amd64.s:1696 +0x1
goroutine 35 [runnable]:
github.com/alesr/strings.Flip(0xc8200727a0, 0x6, 0x0, 0x0)
/Users/Alessandro/GO/src/github.com/alesr/strings/strings.go:33 +0x17e
github.com/alesr/project-euler.Euler4(0x1ac9)
/Users/Alessandro/GO/src/github.com/alesr/project-euler/euler.go:73 +0x95
github.com/alesr/project-euler.TestEulers(0xc8200b6000)
/Users/Alessandro/GO/src/github.com/alesr/project-euler/euler_test.go:11 +0x63
testing.tRunner(0xc8200b6000, 0x2f7340)
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/testing/testing.go:456 +0xdd
created by testing.RunTests
/private/var/folders/q8/bf_4b1ts2zj0l7b0p1dv36lr0000gp/T/workdir/go/src/testing/testing.go:561 +0xaa4
exit status 2
FAIL github.com/alesr/project-euler 0.022s
But still, I checked every single function and they work just as expected. You can access the Euler source code or the packages numbers and strings if you want.
At Euler2 function I have a defer statement to close the channel which is receiving from FibonacciGen.
And on FibonacciGen I do have another defer statement to close the same channel.
It seems that's the my first error. I should have just one and not two statements to close the channel, since they are trying to close the same thing. Is that correct?
Second (and here I'm even a little more unsure), the defer statement will prevent the function to be called until the main goroutine returns, right? Independently if I call it on the package main or not?
Plus, since the data is flowing through the channel from FibonacciGen to the main function. It seems for me, that if I close the channel at FibonacciGen I don't need to notify the main function. But If I close the channel on the main function I do have to notify FibonacciGen to stop trying to send to this channel.
