From 41aa0349a07e63540bd50bcaf1c5731e123d809c Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sun, 8 Oct 2023 16:06:52 -0400
Subject: [PATCH] Add tests for coalesce_whitespace_escaped.

---
 src/types/util.rs | 122 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 101 insertions(+), 21 deletions(-)

diff --git a/src/types/util.rs b/src/types/util.rs
index e8980ea..7eab912 100644
--- a/src/types/util.rs
+++ b/src/types/util.rs
@@ -314,9 +314,10 @@ fn impl_coalesce_whitespace_escaped<'s, C: Fn(char) -> bool>(
                     ret,
                 },
                 c,
-            ) if c == escape_character => {
-                CoalesceWhitespaceEscaped::RequiresMutationEscaping { ret }
-            }
+            ) if c == escape_character => CoalesceWhitespaceEscaped::RequiresMutationEscaping {
+                ret,
+                matched_escape_character: c,
+            },
             (
                 CoalesceWhitespaceEscaped::RequiresMutation {
                     mut in_whitespace,
@@ -332,7 +333,7 @@ fn impl_coalesce_whitespace_escaped<'s, C: Fn(char) -> bool>(
             }
             (
                 CoalesceWhitespaceEscaped::RequiresMutation {
-                    in_whitespace,
+                    in_whitespace: _,
                     mut ret,
                 },
                 _,
@@ -343,9 +344,13 @@ fn impl_coalesce_whitespace_escaped<'s, C: Fn(char) -> bool>(
                     ret,
                 }
             }
-            (CoalesceWhitespaceEscaped::RequiresMutationEscaping { mut ret }, c)
-                if escapable_characters(c) =>
-            {
+            (
+                CoalesceWhitespaceEscaped::RequiresMutationEscaping {
+                    mut ret,
+                    matched_escape_character: _,
+                },
+                c,
+            ) if escapable_characters(c) => {
                 ret.push(c);
                 CoalesceWhitespaceEscaped::RequiresMutation {
                     in_whitespace: false,
@@ -353,7 +358,10 @@ fn impl_coalesce_whitespace_escaped<'s, C: Fn(char) -> bool>(
                 }
             }
             (
-                CoalesceWhitespaceEscaped::RequiresMutationEscaping { mut ret },
+                CoalesceWhitespaceEscaped::RequiresMutationEscaping {
+                    mut ret,
+                    matched_escape_character: _,
+                },
                 ' ' | '\t' | '\r' | '\n',
             ) => {
                 ret.push(' ');
@@ -362,8 +370,14 @@ fn impl_coalesce_whitespace_escaped<'s, C: Fn(char) -> bool>(
                     ret,
                 }
             }
-            (CoalesceWhitespaceEscaped::RequiresMutationEscaping { mut ret }, c) => {
-                ret.push(escape_character);
+            (
+                CoalesceWhitespaceEscaped::RequiresMutationEscaping {
+                    mut ret,
+                    matched_escape_character,
+                },
+                c,
+            ) => {
+                ret.push(matched_escape_character);
                 ret.push(c);
                 // TODO
                 CoalesceWhitespaceEscaped::RequiresMutation {
@@ -373,19 +387,85 @@ fn impl_coalesce_whitespace_escaped<'s, C: Fn(char) -> bool>(
             }
         }
     }
-    // match state {
-    //     CoalesceWhitespaceEscaped::Normal => Cow::Borrowed(input),
-    //     CoalesceWhitespaceEscaped::RequiresMutation {
-    //         in_whitespace: _,
-    //         ret,
-    //     } => Cow::Owned(ret),
-    // }
-    todo!()
+    match state {
+        CoalesceWhitespaceEscaped::Normal => Cow::Borrowed(input),
+        CoalesceWhitespaceEscaped::NormalEscaping { escape_offset: _ } => Cow::Borrowed(input),
+        CoalesceWhitespaceEscaped::RequiresMutation {
+            in_whitespace: _,
+            ret,
+        } => Cow::Owned(ret),
+        CoalesceWhitespaceEscaped::RequiresMutationEscaping {
+            mut ret,
+            matched_escape_character,
+        } => {
+            ret.push(matched_escape_character);
+            Cow::Owned(ret)
+        }
+    }
 }
 
 enum CoalesceWhitespaceEscaped {
     Normal,
-    NormalEscaping { escape_offset: usize },
-    RequiresMutation { in_whitespace: bool, ret: String },
-    RequiresMutationEscaping { ret: String },
+    NormalEscaping {
+        escape_offset: usize,
+    },
+    RequiresMutation {
+        in_whitespace: bool,
+        ret: String,
+    },
+    RequiresMutationEscaping {
+        ret: String,
+        matched_escape_character: char,
+    },
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn coalesce_whitespace_escaped_default() -> Result<(), Box<dyn std::error::Error>> {
+        let input = "foobarbaz";
+        let output = coalesce_whitespace_escaped('&', |c| "".contains(c))(input);
+        assert_eq!(output, "foobarbaz");
+        assert!(matches!(output, Cow::Borrowed(_)));
+        Ok(())
+    }
+
+    #[test]
+    fn coalesce_whitespace_escaped_whitespace_single() -> Result<(), Box<dyn std::error::Error>> {
+        let input = "foo bar baz";
+        let output = coalesce_whitespace_escaped('&', |c| "".contains(c))(input);
+        assert_eq!(output, "foo bar baz");
+        // TODO: Technically this should be a Borrowed but to keep the code simple for now we are treating all whitespace as causing ownership.
+        assert!(matches!(output, Cow::Owned(_)));
+        Ok(())
+    }
+
+    #[test]
+    fn coalesce_whitespace_escaped_whitespace_double() -> Result<(), Box<dyn std::error::Error>> {
+        let input = "foo  bar  baz";
+        let output = coalesce_whitespace_escaped('&', |c| "".contains(c))(input);
+        assert_eq!(output, "foo bar baz");
+        assert!(matches!(output, Cow::Owned(_)));
+        Ok(())
+    }
+
+    #[test]
+    fn coalesce_whitespace_escaped_escape_match() -> Result<(), Box<dyn std::error::Error>> {
+        let input = "foo  &bar  baz";
+        let output = coalesce_whitespace_escaped('&', |c| "b".contains(c))(input);
+        assert_eq!(output, "foo bar baz");
+        assert!(matches!(output, Cow::Owned(_)));
+        Ok(())
+    }
+
+    #[test]
+    fn coalesce_whitespace_escaped_escape_mismatch() -> Result<(), Box<dyn std::error::Error>> {
+        let input = "foo  b&ar  baz";
+        let output = coalesce_whitespace_escaped('&', |c| "b".contains(c))(input);
+        assert_eq!(output, "foo b&ar baz");
+        assert!(matches!(output, Cow::Owned(_)));
+        Ok(())
+    }
 }