assertvalue

assert on steroids that writes and updates tests for you. Golang implementation of https://github.com/assert-value

Usage

You can start with no expected value

// example_test.go
package mypackage

import (
	"github.com/smetana/assert_value_go/assertvalue"
	"testing"
)

func TestExample(t *testing.T) {
	assertvalue.String(t, "Hello World!\n")
}

Run test in verbose mode

go test -v example_test.go

It will ask you about diff

=== RUN   TestExample
@@ -1 +1,2 @@
+Hello World!


Accept new value? [y,n,Y,N] y
--- PASS: TestExample (2.30s)
PASS
ok  	command-line-arguments	2.306s

If you answer "n" the test will fail, but if you answer "y" then expected value will be created (or updated) from actual value and test code will be changed

// example_test.go
package assert_value_go

import (
	"github.com/smetana/assert_value_go/assertvalue"
	"testing"
)

func TestExample(t *testing.T) {
	assertvalue.String(t, "Hello World!\n", `
		Hello World!
	`)
}

Features and Known Issues

String literals as heredocs

Expected values are stored in string literals which are treated as heredocs for better diff readability. This means they ignore common indentation and always end with newlines. When expected value does not end with a newline assertvalue will append a special <NOEOL> string to indicate that last newline should be ignored.

assertvalue.String(t, "Hello World!", `
	Hello World!<NOEOL>
`)

Running tests interactively and non-interactively

assertvalue interacts with user only in verbose mode, when go test is executed with -v flag

# run test interactively in verbose mode
go test -v example_test.go

In normal mode assertvalue works as simple assert function and will fail when expected value not equal actual value

# run test non-interactively in normal mode
go test example_test.go

You can also run test noninteractively in verbose mode using -nointerative command line argument which may be useful for CI testing

# run test non-interactively in verbose mode
go test -v example_test -args -- -nointeractive

API

For now this package is primitive and supports only string expected and actual values

assertvalue.String

Supports two forms

assertvalue.String(t *testing.T, actual string)
assertvalue.String(t *testing.T, actual, expected string)

assertvalue.File

If expected values are big to store them in test code you can store them in files (hello .golden)

assertvalue.File(t *testing.T, actual, filename string)