Make tests fail if rustfmt encounters an error

Previously tests would not fail if they encountered an error such as
LineOverflow or TrailingWhitespace. Making the tests error out will fix
this mismatch between running rustfmt for real and running the tests.

This also modifies all tests that previously contained errors so that
they no longer contain errors (in almost all of the tests this is
accomplished by setting error_on_line_overflow = false).

tests/source/comment4.rs

@@ -18,7 +18,7 @@ fn test() {
          * amet, consectetur adipiscing elit. Aenean ut gravida lorem. Ut turpis
          * felis, pulvinar a semper sed, adipiscing id dolor. */
 
-    // Very looooooooooooooooooooooooooooooooooooooooooooooooooooooooong comment that should be split
+    // Very loooooooooooooooooooooooooooooooooooooooooooooooooooooooong comment that should be split
 
                     // println!("{:?}", rewrite_comment(subslice,
                     //                                       false,

tests/source/enum.rs

@@ -1,4 +1,5 @@
 // rustfmt-wrap_comments: true
+// rustfmt-error_on_line_overflow: false
 // Enums test
 
 #[atrr]

tests/source/file-lines-3.rs

@@ -1,4 +1,5 @@
-// rustfmt-file_lines: [{"file":"tests/source/file-lines-3.rs","range":[4,8]},{"file":"tests/source/file-lines-3.rs","range":[10,15]}]
+// rustfmt-file_lines: [{"file":"tests/source/file-lines-3.rs","range":[5,9]},{"file":"tests/source/file-lines-3.rs","range":[11,16]}]
+// rustfmt-error_on_line_overflow: false
 
 fn floaters() {
     let x = Foo {

tests/source/hard-tabs.rs

@@ -2,6 +2,7 @@
 // rustfmt-single_line_if_else_max_width: 0
 // rustfmt-wrap_comments: true
 // rustfmt-hard_tabs: true
+// rustfmt-error_on_line_overflow: false
 
 fn main() {
 let x = Bar;

tests/source/imports.rs

@@ -1,4 +1,5 @@
 // rustfmt-normalize_comments: true
+// rustfmt-error_on_line_overflow: false
 
 // Imports.
 

tests/source/issue-913.rs

@@ -1,3 +1,5 @@
+// rustfmt-error_on_line_overflow: false
+
 mod client {
     impl Client {
         fn test(self) -> Result<()> {
@@ -10,7 +12,7 @@ mod client {
             let next_state = match self.state {
                 State::V5(v5::State::Command(v5::comand::State::WriteVersion(ref mut response))) => {
                     // The pattern cannot be formatted in a way that the match stays
-                    // within the column limit. The rewrite should therefore be 
+                    // within the column limit. The rewrite should therefore be
                     // skipped.
                     let x =  dont . reformat . meeee();
                 }

tests/source/string-lit.rs

@@ -1,4 +1,5 @@
 // rustfmt-force_format_strings: true
+// rustfmt-error_on_line_overflow: false
 // Long string literals
 
 fn main() -> &'static str {

tests/source/string_punctuation.rs

@@ -1,4 +1,5 @@
 // rustfmt-format_strings: true
+// rustfmt-error_on_line_overflow: false
 
 fn main() {
     println!("ThisIsAReallyLongStringWithNoSpaces.It_should_prefer_to_break_onpunctuation:Likethisssssssssssss");

tests/source/struct_lits.rs

@@ -1,5 +1,6 @@
 // rustfmt-normalize_comments: true
 // rustfmt-wrap_comments: true
+// rustfmt-error_on_line_overflow: false
 // Struct literal expressions.
 
 fn main() {

tests/source/struct_lits_visual.rs

@@ -1,6 +1,7 @@
 // rustfmt-normalize_comments: true
 // rustfmt-wrap_comments: true
 // rustfmt-struct_lit_style: Visual
+// rustfmt-error_on_line_overflow: false
 
 // Struct literal expressions.
 

tests/source/struct_lits_visual_multiline.rs

@@ -2,6 +2,7 @@
 // rustfmt-wrap_comments: true
 // rustfmt-struct_lit_style: Visual
 // rustfmt-struct_lit_multiline_style: ForceMulti
+// rustfmt-error_on_line_overflow: false
 
 // Struct literal expressions.
 

tests/source/structs.rs

@@ -1,5 +1,6 @@
 // rustfmt-normalize_comments: true
 // rustfmt-wrap_comments: true
+// rustfmt-error_on_line_overflow: false
 
                                                                        /// A Doc comment
 #[AnAttribute]

tests/system.rs

@@ -179,6 +179,10 @@ fn check_files<I>(files: I) -> (Vec<FormatReport>, u32, u32)
         println!("Testing '{}'...", file_name);
 
         match idempotent_check(file_name) {
+            Ok(ref report) if report.has_warnings() => {
+                print!("{}", report);
+                fails += 1;
+            }
             Ok(report) => reports.push(report),
             Err(msg) => {
                 print_mismatches(msg);

tests/target/comment4.rs

@@ -18,7 +18,7 @@ fn test() {
      * amet, consectetur adipiscing elit. Aenean ut gravida lorem. Ut turpis
      * felis, pulvinar a semper sed, adipiscing id dolor. */
 
-    // Very looooooooooooooooooooooooooooooooooooooooooooooooooooooooong comment that should be split
+    // Very loooooooooooooooooooooooooooooooooooooooooooooooooooooooong comment that should be split
 
     // println!("{:?}", rewrite_comment(subslice,
     //                                       false,

tests/target/enum.rs

@@ -1,4 +1,5 @@
 // rustfmt-wrap_comments: true
+// rustfmt-error_on_line_overflow: false
 // Enums test
 
 #[atrr]

tests/target/file-lines-3.rs

@@ -1,4 +1,5 @@
-// rustfmt-file_lines: [{"file":"tests/source/file-lines-3.rs","range":[4,8]},{"file":"tests/source/file-lines-3.rs","range":[10,15]}]
+// rustfmt-file_lines: [{"file":"tests/source/file-lines-3.rs","range":[5,9]},{"file":"tests/source/file-lines-3.rs","range":[11,16]}]
+// rustfmt-error_on_line_overflow: false
 
 fn floaters() {
     let x = Foo {

tests/target/hard-tabs.rs

@@ -2,6 +2,7 @@
 // rustfmt-single_line_if_else_max_width: 0
 // rustfmt-wrap_comments: true
 // rustfmt-hard_tabs: true
+// rustfmt-error_on_line_overflow: false
 
 fn main() {
 	let x = Bar;

tests/target/imports.rs

@@ -1,4 +1,5 @@
 // rustfmt-normalize_comments: true
+// rustfmt-error_on_line_overflow: false
 
 // Imports.
 

tests/target/issue-913.rs

@@ -1,3 +1,5 @@
+// rustfmt-error_on_line_overflow: false
+
 mod client {
     impl Client {
         fn test(self) -> Result<()> {
@@ -10,7 +12,7 @@ mod client {
             let next_state = match self.state {
                 State::V5(v5::State::Command(v5::comand::State::WriteVersion(ref mut response))) => {
                     // The pattern cannot be formatted in a way that the match stays
-                    // within the column limit. The rewrite should therefore be 
+                    // within the column limit. The rewrite should therefore be
                     // skipped.
                     let x =  dont . reformat . meeee();
                 }

tests/target/string-lit.rs

@@ -1,4 +1,5 @@
 // rustfmt-force_format_strings: true
+// rustfmt-error_on_line_overflow: false
 // Long string literals
 
 fn main() -> &'static str {

tests/target/string_punctuation.rs

@@ -1,4 +1,5 @@
 // rustfmt-format_strings: true
+// rustfmt-error_on_line_overflow: false
 
 fn main() {
     println!("ThisIsAReallyLongStringWithNoSpaces.It_should_prefer_to_break_onpunctuation:\

tests/target/struct_lits.rs

@@ -1,5 +1,6 @@
 // rustfmt-normalize_comments: true
 // rustfmt-wrap_comments: true
+// rustfmt-error_on_line_overflow: false
 // Struct literal expressions.
 
 fn main() {

tests/target/struct_lits_visual.rs

@@ -1,6 +1,7 @@
 // rustfmt-normalize_comments: true
 // rustfmt-wrap_comments: true
 // rustfmt-struct_lit_style: Visual
+// rustfmt-error_on_line_overflow: false
 
 // Struct literal expressions.
 

tests/target/struct_lits_visual_multiline.rs

@@ -2,6 +2,7 @@
 // rustfmt-wrap_comments: true
 // rustfmt-struct_lit_style: Visual
 // rustfmt-struct_lit_multiline_style: ForceMulti
+// rustfmt-error_on_line_overflow: false
 
 // Struct literal expressions.
 

tests/target/structs.rs

@@ -1,5 +1,6 @@
 // rustfmt-normalize_comments: true
 // rustfmt-wrap_comments: true
+// rustfmt-error_on_line_overflow: false
 
 /// A Doc comment
 #[AnAttribute]