fix tests

testcrate/tests/compile-fail/enum-with-discriminants.rs

@@ -8,3 +8,5 @@ enum Enum {
     Foo,
     Bar = 42,
 }
+
+fn main() {}

testcrate/tests/compile-fail/enum-zero-variants.rs

@@ -5,3 +5,5 @@ extern crate derive_new;
 //~^ ERROR proc-macro derive
 //~^^ HELP #[derive(new)] cannot be implemented for enums with zero variants
 enum Enum {}
+
+fn main() {}

testcrate/tests/compile-fail/multiple-new-attrs.rs

@@ -10,3 +10,5 @@ struct Foo {
     #[new(value = "42")]
     y: i32,
 }
+
+fn main() {}

testcrate/tests/compile-fail/new-invalid-attr-type.rs

@@ -8,3 +8,5 @@ struct Foo {
     #[new = "foo"]
     x: i32,
 }
+
+fn main() {}

testcrate/tests/compile-fail/new-invalid-value.rs

@@ -5,6 +5,8 @@ extern crate derive_new;
 //~^ ERROR produced unparsable tokens
 struct Foo {
     #[new(value = "hello@world")]
-//~^ ERROR expected one of
+    //~^ ERROR expected one of
     x: i32,
 }
+
+fn main() {}

testcrate/tests/compile-fail/new-list-invalid.rs

@@ -8,3 +8,5 @@ struct Foo {
     #[new(foo)]
     x: i32,
 }
+
+fn main() {}

testcrate/tests/compile-fail/new-name-value-invalid.rs

@@ -8,3 +8,5 @@ struct Foo {
     #[new(foo = "bar")]
     x: i32,
 }
+
+fn main() {}

testcrate/tests/compile-fail/new-nested-list.rs

@@ -8,3 +8,5 @@ struct Foo {
     #[new(foo("bar"))]
     x: i32,
 }
+
+fn main() {}

testcrate/tests/compile-fail/new-nested-literal.rs

@@ -3,8 +3,10 @@ extern crate derive_new;
 
 #[derive(new)]
 //~^ ERROR proc-macro derive
-//~^^ HELP Invalid #[new] attribute: literal value in #[new(..)]
+//~^^ HELP Invalid #[new] attribute: expected identifier
 struct Foo {
     #[new("foo")]
     x: i32,
 }
+
+fn main() {}

testcrate/tests/compile-fail/new-non-literal-value.rs

@@ -8,3 +8,5 @@ struct Foo {
     #[new(value = false)]
     x: i32,
 }
+
+fn main() {}