feat(safety): added NoFileDescriptorLeak (linux) (#62)

This is a linux-only assertion to guard against file descritor leaks.

Unlike goroutine leak checks, this one does not support parallel tests.

tests: skip testable examples for NoFileDescriptorLeak on windows/macos

Signed-off-by: Frederic BIDON <fredbi@yahoo.com>

Author: fredbi

assert/assert_assertions.go

@@ -8,6 +8,7 @@ import (
   "fmt"
   "net/http"
   "path/filepath"
+  "runtime"
   "testing"
   "github.com/go-openapi/testify/v2/{{ .Package }}"
 {{ imports .Imports }}
@@ -25,6 +26,20 @@ import (
 
 func Example{{ .Name }}() {
     {{- $fn := . }}
+    {{- if eq $fn.Name "NoFileDescriptorLeak" }}{{/* handle special case for platform-specific assertion: example only runs on windows */}}
+    if runtime.GOOS != "linux" {
+      // This example is only runnable on linux. On other platforms, the assertion skips the test.
+      // We force the expected output below, so that tests don't fail on other platforms. 
+      {{- if eq $pkg "require" }}
+      fmt.Println("passed")
+      {{- else }}
+      fmt.Println("success: true")
+      {{- end }}
+
+      return
+    }
+    {{ cr false }}
+    {{- end }}
     {{- range .Tests }}
       {{- if .IsSuccess }}
         {{- cr .IsFirst }}

assert/assert_assertions_test.go

@@ -43,7 +43,7 @@ Each domain contains assertions regrouped by their use case (e.g. http, json, er
 - [Number](./number.md) - Asserting Numbers (7)
 - [Ordering](./ordering.md) - Asserting How Collections Are Ordered (10)
 - [Panic](./panic.md) - Asserting A Panic Behavior (4)
-- [Safety](./safety.md) - Checks Against Leaked Resources (1)
+- [Safety](./safety.md) - Checks Against Leaked Resources (Goroutines, File Descriptors) (2)
 - [String](./string.md) - Asserting Strings (4)
 - [Testing](./testing.md) - Mimics Methods From The Testing Standard Library (2)
 - [Time](./time.md) - Asserting Times And Durations (2)