diff --git a/resources/optional_labels.lp b/resources/optional_labels.lp
index 003c11c..c00ff9b 100644
--- a/resources/optional_labels.lp
+++ b/resources/optional_labels.lp
@@ -3,7 +3,7 @@
 Minimize
 x + 10 y
 Subject To
-r01:  x + y  >= 1
+-x + 2y  >= 1
 
 Binaries
  x y z a
diff --git a/src/lp_file_format.pest b/src/lp_file_format.pest
index f7d3eb7..89aa808 100644
--- a/src/lp_file_format.pest
+++ b/src/lp_file_format.pest
@@ -97,7 +97,7 @@ LTE                =  { "<=" }
 EQ                 =  { "=" }
 CMP                = _{ GTE | GT | LTE | LT | EQ }
 CONSTRAINT_EXPR    =  { OPERATOR? ~ FLOAT? ~ VARIABLE | OPERATOR? ~ FLOAT }
-CONSTRAINT_NAME    = ${ VALID_CHARS{1, 255} }
+CONSTRAINT_NAME    = ${ VALID_CHARS{1, 255} ~ COLON }
 CONSTRAINT         =  {
     NEWLINE* ~ (CONSTRAINT_NAME ~ COLON*)? ~ CONSTRAINT_EXPR ~ (NEWLINE? ~ OPERATOR ~ CONSTRAINT_EXPR)* ~ NEWLINE? ~ CMP ~ FLOAT
 }
diff --git a/src/lp_parts.rs b/src/lp_parts.rs
index 93f2c9a..6335c80 100644
--- a/src/lp_parts.rs
+++ b/src/lp_parts.rs
@@ -23,9 +23,14 @@ fn compose_objective(pair: Pair<'_, Rule>, gen: &mut ShortCodeGenerator<char>) -
 }
 
 #[allow(clippy::unwrap_used)]
-fn compose_constraint(pair: Pair<'_, Rule>) -> anyhow::Result<Constraint> {
-    let mut parts = pair.into_inner();
-    let name = parts.next().unwrap().as_str().to_string();
+fn compose_constraint(pair: Pair<'_, Rule>, gen: &mut ShortCodeGenerator<char>) -> anyhow::Result<Constraint> {
+    let mut parts = pair.into_inner().peekable();
+    // Constraint name can be omitted in LP files, so we need to handle that case
+    let name = if parts.peek().unwrap().as_rule() == Rule::CONSTRAINT_NAME {
+        parts.next().unwrap().as_str().to_string()
+    } else {
+        format!("con_{}", gen.next_string())
+    };
     let mut coefficients: Vec<_> = vec![];
     while let Some(p) = parts.peek() {
         if p.as_rule().is_cmp() {
@@ -33,7 +38,8 @@ fn compose_constraint(pair: Pair<'_, Rule>) -> anyhow::Result<Constraint> {
         }
         coefficients.push(parts.next().unwrap());
     }
-    let coefficients: anyhow::Result<Vec<_>> = coefficients.into_iter().map(|p| p.into_inner().try_into()).collect();
+    let coefficients: anyhow::Result<Vec<_>> =
+        coefficients.into_iter().filter(|p| !matches!(p.as_rule(), Rule::PLUS | Rule::MINUS)).map(|p| p.into_inner().try_into()).collect();
     let sense = parts.next().unwrap().as_str().to_string();
     let rhs = parts.next().unwrap().as_str().parse()?;
     Ok(Constraint::Standard { name, coefficients: coefficients?, sense, rhs })
@@ -105,7 +111,8 @@ pub fn compose(pair: Pair<'_, Rule>, mut parsed: LPProblem, gen: &mut ShortCodeG
         }
         // Problem Constraints
         Rule::CONSTRAINTS => {
-            let constraints: anyhow::Result<Vec<Constraint>> = pair.into_inner().map(|inner_pair| compose_constraint(inner_pair)).collect();
+            let constraints: anyhow::Result<Vec<Constraint>> =
+                pair.into_inner().map(|inner_pair| compose_constraint(inner_pair, gen)).collect();
             parsed.add_constraints(constraints?);
         }
         Rule::SOS => {
diff --git a/tests/test_from_file.rs b/tests/test_from_file.rs
index b6c854e..daf1572 100644
--- a/tests/test_from_file.rs
+++ b/tests/test_from_file.rs
@@ -11,23 +11,23 @@ macro_rules! generate_test {
         #[test]
         fn $test_name() {
             let result = read_file_from_resources($file).unwrap();
-            // dbg!(&result);
+            dbg!(&result);
             assert_eq!(result.problem_sense, Sense::$sense);
-            assert_eq!(result.objectives.len(), $obj_len);
-            assert_eq!(result.constraints.len(), $con_len);
-            assert_eq!(result.variables.len(), $var_len);
+            assert_eq!(result.objectives.len(), $obj_len, "Failed Objective Count");
+            assert_eq!(result.constraints.len(), $con_len, "Failed Constraint Count");
+            assert_eq!(result.variables.len(), $var_len, "Failed Variable Count");
         }
     };
     ($test_name:ident, $file:expr, $name:expr, $sense:ident, $obj_len:expr, $con_len:expr, $var_len:expr) => {
         #[test]
         fn $test_name() {
             let result = read_file_from_resources($file).unwrap();
-            // dbg!(&result);
+            dbg!(&result);
             assert_eq!($name, result.problem_name);
             assert_eq!(result.problem_sense, Sense::$sense);
-            assert_eq!(result.objectives.len(), $obj_len);
-            assert_eq!(result.constraints.len(), $con_len);
-            assert_eq!(result.variables.len(), $var_len);
+            assert_eq!(result.objectives.len(), $obj_len, "Failed Objective Count");
+            assert_eq!(result.constraints.len(), $con_len, "Failed Constraint Count");
+            assert_eq!(result.variables.len(), $var_len, "Failed Variable Count");
         }
     };
 }