test: Add negative test for wrong file skipping

internal/testdata/snapshots/input/testspecial/foo.go

@@ -0,0 +1,3 @@
+package testspecial
+
+func Foo() {}

internal/testdata/snapshots/input/testspecial/foo_other_test.go

@@ -0,0 +1,9 @@
+package testspecial_test
+
+import (
+	"testing"
+
+	"sg/testspecial"
+)
+
+func TestFoo_Blackbox(*testing.T) { testspecial.Foo() }

internal/testdata/snapshots/input/testspecial/foo_test.go

@@ -0,0 +1,3 @@
+package testspecial
+
+func TestFoo_Whitebox() { Foo() }

internal/testdata/snapshots/input/testspecial/go.mod

@@ -0,0 +1,3 @@
+module sg/testspecial
+
+go 1.19

internal/testdata/snapshots/output/testspecial/foo.go

@@ -0,0 +1,12 @@
+  package testspecial
+//        ^^^^^^^^^^^ definition 0.1.test `sg/testspecial`/
+//        documentation
+//        > package testspecial
+
+  func Foo() {}
+//     ^^^ definition 0.1.test `sg/testspecial`/Foo().
+//     documentation
+//     > ```go
+//     > func Foo()
+//     > ```
+

internal/testdata/snapshots/output/testspecial/foo_other_test.go

@@ -0,0 +1,24 @@
+  package testspecial_test
+//        ^^^^^^^^^^^^^^^^ definition 0.1.test `sg/testspecial_test`/
+//        documentation
+//        > package testspecial_test
+
+  import (
+   "testing"
+//  ^^^^^^^ reference github.com/golang/go/src go1.22 testing/
+
+   "sg/testspecial"
+//  ^^^^^^^^^^^^^^ reference 0.1.test `sg/testspecial`/
+  )
+
+  func TestFoo_Blackbox(*testing.T) { testspecial.Foo() }
+//     ^^^^^^^^^^^^^^^^ definition 0.1.test `sg/testspecial_test`/TestFoo_Blackbox().
+//     documentation
+//     > ```go
+//     > func TestFoo_Blackbox(*T)
+//     > ```
+//                       ^^^^^^^ reference github.com/golang/go/src go1.22 testing/
+//                               ^ reference github.com/golang/go/src go1.22 testing/T#
+//                                    ^^^^^^^^^^^ reference 0.1.test `sg/testspecial`/
+//                                                ^^^ reference 0.1.test `sg/testspecial`/Foo().
+