needless_continue: Add tests for helper functions to the needless_continue lint.

Creating a test file per function sounds a bit excessive, so just
clubbing all needless_continue specific function tests into this module.

tests/needless_continue_helpers.rs

@@ -0,0 +1,89 @@
+// Tests for the various helper functions used by the needless_continue
+// lint that don't belong in utils.
+extern crate clippy_lints;
+use clippy_lints::needless_continue::{erode_from_back, erode_block, erode_from_front};
+
+#[test]
+#[cfg_attr(rustfmt, rustfmt_skip)]
+fn test_erode_from_back() {
+    let input = "\
+{
+    let x = 5;
+    let y = format!(\"{}\", 42);
+}";
+
+    let expected = "\
+{
+    let x = 5;
+    let y = format!(\"{}\", 42);";
+
+    let got = erode_from_back(input);
+    assert_eq!(expected, got);
+}
+
+#[test]
+#[cfg_attr(rustfmt, rustfmt_skip)]
+fn test_erode_from_back_no_brace() {
+    let input = "\
+let x = 5;
+let y = something();
+";
+    let expected = "";
+    let got = erode_from_back(input);
+    assert_eq!(expected, got);
+}
+
+#[test]
+#[cfg_attr(rustfmt, rustfmt_skip)]
+fn test_erode_from_front() {
+    let input = "
+        {
+            something();
+            inside_a_block();
+        }
+    ";
+    let expected =
+"            something();
+            inside_a_block();
+        }
+    ";
+    let got = erode_from_front(input);
+    println!("input: {}\nexpected:\n{}\ngot:\n{}", input, expected, got);
+    assert_eq!(expected, got);
+}
+
+#[test]
+#[cfg_attr(rustfmt, rustfmt_skip)]
+fn test_erode_from_front_no_brace() {
+    let input = "
+            something();
+            inside_a_block();
+    ";
+    let expected =
+"something();
+            inside_a_block();
+    ";
+    let got = erode_from_front(input);
+    println!("input: {}\nexpected:\n{}\ngot:\n{}", input, expected, got);
+    assert_eq!(expected, got);
+}
+
+
+#[test]
+#[cfg_attr(rustfmt, rustfmt_skip)]
+fn test_erode_block() {
+
+    let input = "
+        {
+            something();
+            inside_a_block();
+        }
+    ";
+    let expected =
+"            something();
+            inside_a_block();";
+    let got = erode_block(input);
+    println!("input: {}\nexpected:\n{}\ngot:\n{}", input, expected, got);
+    assert_eq!(expected, got);
+}
+