Feature: migrate tool (#5)

* feature: new string matcher

* feature: migrate tool

* fix: remove dependency to slices package

README.md

@@ -103,6 +103,7 @@ Expectation | Type constraints | Description
 `is.StringContaining` | `string` | Expects the given value to be a string containing a given substring
 `is.StringHavingPrefix` | `string` | Expects the given value to be a string having a given prefix
 `is.StringHavingSuffix` | `string` | Expects the given value to be a string having a given suffix
+`is.EqualToStringByLines` | `string` | Similar to EqualTo used on two strings but reports differences on a line-by-line basis
 
 ### Deep equality
 

cmd/expect-migrate/README.md

@@ -0,0 +1,58 @@
+# expect-migrate
+
+`expect-migrate` is a small command line tool to upgrade your go test source files
+using `github.com/halimath/[email protected]` to `github.com/halimath/expect@latest`. The tool rewrites
+go source files that in a lot of cases directly compile and run. In some cases minor work by the developer
+is needed.
+
+# Installation
+
+```shell
+go install github.com/halimath/expect/cmd/expect-migrate@main
+```
+
+# Usage
+
+Given an input file `some_test.go`
+
+```go
+package some
+
+import (
+	"testing"
+	. "github.com/halimath/expect-go"
+)
+
+func TestSomething(t *testing.T) {
+	var err error
+	s := produceValue()
+
+	EnsureThat(t, err).Is(NoError())
+	ExpectThat(t, s).Is(Equal("foo"))
+}
+```
+
+applying
+
+```shell
+expect-migrate some_test.go
+```
+
+will rewrite the file to 
+
+```go
+package some
+
+import (
+	"testing"
+	"github.com/halimath/expect"
+	"github.com/halimath/expect/is"
+)
+
+func TestSomething(t *testing.T) {
+	var err error
+	s := produceValue()
+	expect.That(t, expect.FailNow(is.NoError(err)))
+	expect.That(t, is.EqualTo(s, "foo"))
+}
+```