diff --git a/src/format/formulas.rs b/src/format/formulas.rs
index 580b3a8..b734875 100644
--- a/src/format/formulas.rs
+++ b/src/format/formulas.rs
@@ -381,7 +381,6 @@ mod tests
 	use crate::*;
 	use crate::format::terms::tests::*;
 
-	// Tests all neutral intermediates (such as 1-ary conjunction)
 	macro_rules! assert
 	{
 		($formula:expr, $output:expr) =>
diff --git a/src/format/terms.rs b/src/format/terms.rs
index 59cd3bf..4f27aa7 100644
--- a/src/format/terms.rs
+++ b/src/format/terms.rs
@@ -259,6 +259,14 @@ pub(crate) mod tests
 {
 	use crate::*;
 
+	macro_rules! assert
+	{
+		($term:expr, $output:expr) =>
+		{
+			assert_eq!(format($term), $output);
+		};
+	}
+
 	fn format(term: Box<ast::Term>) -> String
 	{
 		format!("{}", term)
@@ -392,71 +400,68 @@ pub(crate) mod tests
 	#[test]
 	fn format_binary_operation()
 	{
-		assert_eq!(format(add(constant("a"), constant("b"))), "a + b");
-		assert_eq!(format(subtract(constant("a"), constant("b"))), "a - b");
-		assert_eq!(format(multiply(constant("a"), constant("b"))), "a * b");
-		assert_eq!(format(divide(constant("a"), constant("b"))), "a / b");
-		assert_eq!(format(modulo(constant("a"), constant("b"))), "a % b");
-		assert_eq!(format(exponentiate(constant("a"), constant("b"))), "a ** b");
+		assert!(add(constant("a"), constant("b")), "a + b");
+		assert!(subtract(constant("a"), constant("b")), "a - b");
+		assert!(multiply(constant("a"), constant("b")), "a * b");
+		assert!(divide(constant("a"), constant("b")), "a / b");
+		assert!(modulo(constant("a"), constant("b")), "a % b");
+		assert!(exponentiate(constant("a"), constant("b")), "a ** b");
 	}
 
 	#[test]
 	fn format_boolean()
 	{
-		assert_eq!(format(true_()), "true");
-		assert_eq!(format(false_()), "false");
+		assert!(true_(), "true");
+		assert!(false_(), "false");
 	}
 
 	#[test]
 	fn format_special_integer()
 	{
-		assert_eq!(format(infimum()), "#inf");
-		assert_eq!(format(supremum()), "#sup");
+		assert!(infimum(), "#inf");
+		assert!(supremum(), "#sup");
 	}
 
 	#[test]
 	fn format_integer()
 	{
-		assert_eq!(format(integer(0)), "0");
-		assert_eq!(format(integer(1)), "1");
-		assert_eq!(format(integer(10000)), "10000");
-		assert_eq!(format(integer(-1)), "-1");
-		assert_eq!(format(integer(-10000)), "-10000");
+		assert!(integer(0), "0");
+		assert!(integer(1), "1");
+		assert!(integer(10000), "10000");
+		assert!(integer(-1), "-1");
+		assert!(integer(-10000), "-10000");
 	}
 
 	#[test]
 	fn format_string()
 	{
-		assert_eq!(format(string("")), "\"\"");
-		assert_eq!(format(string(" ")), "\" \"");
-		assert_eq!(format(string("     ")), "\"     \"");
-		assert_eq!(format(string("a")), "\"a\"");
-		assert_eq!(format(string("test test")), "\"test test\"");
-		assert_eq!(format(string("123 123")), "\"123 123\"");
-		assert_eq!(format(string("\ntest\n123\n")), "\"\\ntest\\n123\\n\"");
-		assert_eq!(format(string("\ttest\t123\t")), "\"\\ttest\\t123\\t\"");
-		assert_eq!(format(string("\\test\\123\\")), "\"\\\\test\\\\123\\\\\"");
-		assert_eq!(format(string("🙂test🙂123🙂")), "\"🙂test🙂123🙂\"");
+		assert!(string(""), "\"\"");
+		assert!(string(" "), "\" \"");
+		assert!(string("     "), "\"     \"");
+		assert!(string("a"), "\"a\"");
+		assert!(string("test test"), "\"test test\"");
+		assert!(string("123 123"), "\"123 123\"");
+		assert!(string("\ntest\n123\n"), "\"\\ntest\\n123\\n\"");
+		assert!(string("\ttest\t123\t"), "\"\\ttest\\t123\\t\"");
+		assert!(string("\\test\\123\\"), "\"\\\\test\\\\123\\\\\"");
+		assert!(string("🙂test🙂123🙂"), "\"🙂test🙂123🙂\"");
 	}
 
 	#[test]
 	fn format_function()
 	{
-		assert_eq!(format(constant("a")), "a");
-		assert_eq!(format(constant("constant")), "constant");
-		assert_eq!(format(function("f", vec![constant("a")])), "f(a)");
-		assert_eq!(format(
-			function("f", vec![constant("a"), constant("b"), constant("c")])),
-			"f(a, b, c)");
-		assert_eq!(format(function("function", vec![constant("a"), constant("b"), constant("c")])),
+		assert!(constant("a"), "a");
+		assert!(constant("constant"), "constant");
+		assert!(function("f", vec![constant("a")]), "f(a)");
+		assert!(function("f", vec![constant("a"), constant("b"), constant("c")]), "f(a, b, c)");
+		assert!(function("function", vec![constant("a"), constant("b"), constant("c")]),
 			"function(a, b, c)");
 
-		assert_eq!(format(
-			function("function", vec![
-				exponentiate(absolute_value(multiply(constant("a"), integer(-20))), integer(2)),
-				string("test"),
-				function("f", vec![multiply(add(constant("b"), constant("c")),
-					subtract(constant("b"), constant("c"))), infimum(), variable("X")])])),
+		assert!(function("function", vec![
+			exponentiate(absolute_value(multiply(constant("a"), integer(-20))), integer(2)),
+			string("test"),
+			function("f", vec![multiply(add(constant("b"), constant("c")),
+				subtract(constant("b"), constant("c"))), infimum(), variable("X")])]),
 			"function(|a * -20| ** 2, \"test\", f((b + c) * (b - c), #inf, X))");
 
 		// TODO: escape functions that start with capital letters or that conflict with keywords
@@ -475,232 +480,193 @@ pub(crate) mod tests
 	#[test]
 	fn format_variable()
 	{
-		assert_eq!(format(variable("X")), "X");
-		assert_eq!(format(variable("Variable")), "Variable");
+		assert!(variable("X"), "X");
+		assert!(variable("Variable"), "Variable");
 	}
 
 	#[test]
 	fn format_combination_boolean_and_lower()
 	{
-		assert_eq!(format(function("f", vec![true_(), true_(), true_()])), "f(true, true, true)");
-		assert_eq!(format(
-			function("f", vec![false_(), false_(), false_()])),
-			"f(false, false, false)");
+		assert!(function("f", vec![true_(), true_(), true_()]), "f(true, true, true)");
+		assert!(function("f", vec![false_(), false_(), false_()]), "f(false, false, false)");
 
-		assert_eq!(format(absolute_value(true_())), "|true|");
-		assert_eq!(format(absolute_value(false_())), "|false|");
+		assert!(absolute_value(true_()), "|true|");
+		assert!(absolute_value(false_()), "|false|");
 
-		assert_eq!(format(negative(true_())), "-true");
-		assert_eq!(format(negative(false_())), "-false");
+		assert!(negative(true_()), "-true");
+		assert!(negative(false_()), "-false");
 
-		assert_eq!(format(exponentiate(true_(), true_())), "true ** true");
-		assert_eq!(format(exponentiate(false_(), false_())), "false ** false");
+		assert!(exponentiate(true_(), true_()), "true ** true");
+		assert!(exponentiate(false_(), false_()), "false ** false");
 
-		assert_eq!(format(multiply(true_(), true_())), "true * true");
-		assert_eq!(format(multiply(false_(), false_())), "false * false");
+		assert!(multiply(true_(), true_()), "true * true");
+		assert!(multiply(false_(), false_()), "false * false");
 
-		assert_eq!(format(divide(true_(), true_())), "true / true");
-		assert_eq!(format(divide(false_(), false_())), "false / false");
+		assert!(divide(true_(), true_()), "true / true");
+		assert!(divide(false_(), false_()), "false / false");
 
-		assert_eq!(format(modulo(true_(), true_())), "true % true");
-		assert_eq!(format(modulo(false_(), false_())), "false % false");
+		assert!(modulo(true_(), true_()), "true % true");
+		assert!(modulo(false_(), false_()), "false % false");
 
-		assert_eq!(format(add(true_(), true_())), "true + true");
-		assert_eq!(format(add(false_(), false_())), "false + false");
+		assert!(add(true_(), true_()), "true + true");
+		assert!(add(false_(), false_()), "false + false");
 
-		assert_eq!(format(subtract(true_(), true_())), "true - true");
-		assert_eq!(format(subtract(false_(), false_())), "false - false");
+		assert!(subtract(true_(), true_()), "true - true");
+		assert!(subtract(false_(), false_()), "false - false");
 	}
 
 	#[test]
 	fn format_combination_special_integer_and_lower()
 	{
-		assert_eq!(format(
-			function("f", vec![infimum(), infimum(), infimum()])),
-			"f(#inf, #inf, #inf)");
-		assert_eq!(format(
-			function("f", vec![supremum(), supremum(), supremum()])),
-			"f(#sup, #sup, #sup)");
+		assert!(function("f", vec![infimum(), infimum(), infimum()]), "f(#inf, #inf, #inf)");
+		assert!(function("f", vec![supremum(), supremum(), supremum()]), "f(#sup, #sup, #sup)");
 
-		assert_eq!(format(absolute_value(infimum())), "|#inf|");
-		assert_eq!(format(absolute_value(supremum())), "|#sup|");
+		assert!(absolute_value(infimum()), "|#inf|");
+		assert!(absolute_value(supremum()), "|#sup|");
 
-		assert_eq!(format(negative(infimum())), "-#inf");
-		assert_eq!(format(negative(supremum())), "-#sup");
+		assert!(negative(infimum()), "-#inf");
+		assert!(negative(supremum()), "-#sup");
 
-		assert_eq!(format(exponentiate(infimum(), infimum())), "#inf ** #inf");
-		assert_eq!(format(exponentiate(supremum(), supremum())), "#sup ** #sup");
+		assert!(exponentiate(infimum(), infimum()), "#inf ** #inf");
+		assert!(exponentiate(supremum(), supremum()), "#sup ** #sup");
 
-		assert_eq!(format(multiply(infimum(), infimum())), "#inf * #inf");
-		assert_eq!(format(multiply(supremum(), supremum())), "#sup * #sup");
+		assert!(multiply(infimum(), infimum()), "#inf * #inf");
+		assert!(multiply(supremum(), supremum()), "#sup * #sup");
 
-		assert_eq!(format(divide(infimum(), infimum())), "#inf / #inf");
-		assert_eq!(format(divide(supremum(), supremum())), "#sup / #sup");
+		assert!(divide(infimum(), infimum()), "#inf / #inf");
+		assert!(divide(supremum(), supremum()), "#sup / #sup");
 
-		assert_eq!(format(modulo(infimum(), infimum())), "#inf % #inf");
-		assert_eq!(format(modulo(supremum(), supremum())), "#sup % #sup");
+		assert!(modulo(infimum(), infimum()), "#inf % #inf");
+		assert!(modulo(supremum(), supremum()), "#sup % #sup");
 
-		assert_eq!(format(add(infimum(), infimum())), "#inf + #inf");
-		assert_eq!(format(add(supremum(), supremum())), "#sup + #sup");
+		assert!(add(infimum(), infimum()), "#inf + #inf");
+		assert!(add(supremum(), supremum()), "#sup + #sup");
 
-		assert_eq!(format(subtract(infimum(), infimum())), "#inf - #inf");
-		assert_eq!(format(subtract(supremum(), supremum())), "#sup - #sup");
+		assert!(subtract(infimum(), infimum()), "#inf - #inf");
+		assert!(subtract(supremum(), supremum()), "#sup - #sup");
 	}
 
 	#[test]
 	fn format_combination_integer_and_lower()
 	{
-		assert_eq!(format(
-			function("f", vec![integer(0), integer(0), integer(0)])),
-			"f(0, 0, 0)");
-		assert_eq!(format(
-			function("f", vec![integer(10000), integer(10000), integer(10000)])),
+		assert!(function("f", vec![integer(0), integer(0), integer(0)]), "f(0, 0, 0)");
+		assert!(function("f", vec![integer(10000), integer(10000), integer(10000)]),
 			"f(10000, 10000, 10000)");
-		assert_eq!(format(
-			function("f", vec![integer(-10000), integer(-10000), integer(-10000)])),
+		assert!(function("f", vec![integer(-10000), integer(-10000), integer(-10000)]),
 			"f(-10000, -10000, -10000)");
 
-		assert_eq!(format(absolute_value(integer(0))), "|0|");
-		assert_eq!(format(absolute_value(integer(10000))), "|10000|");
-		assert_eq!(format(absolute_value(integer(-10000))), "|-10000|");
+		assert!(absolute_value(integer(0)), "|0|");
+		assert!(absolute_value(integer(10000)), "|10000|");
+		assert!(absolute_value(integer(-10000)), "|-10000|");
 
-		assert_eq!(format(negative(integer(0))), "-0");
-		assert_eq!(format(negative(integer(10000))), "-10000");
-		assert_eq!(format(negative(integer(-10000))), "--10000");
+		assert!(negative(integer(0)), "-0");
+		assert!(negative(integer(10000)), "-10000");
+		assert!(negative(integer(-10000)), "--10000");
 
-		assert_eq!(format(exponentiate(integer(0), integer(0))), "0 ** 0");
-		assert_eq!(format(exponentiate(integer(10000), integer(10000))), "10000 ** 10000");
-		assert_eq!(format(exponentiate(integer(-10000), integer(-10000))), "-10000 ** -10000");
+		assert!(exponentiate(integer(0), integer(0)), "0 ** 0");
+		assert!(exponentiate(integer(10000), integer(10000)), "10000 ** 10000");
+		assert!(exponentiate(integer(-10000), integer(-10000)), "-10000 ** -10000");
 
-		assert_eq!(format(multiply(integer(0), integer(0))), "0 * 0");
-		assert_eq!(format(multiply(integer(10000), integer(10000))), "10000 * 10000");
-		assert_eq!(format(multiply(integer(-10000), integer(-10000))), "-10000 * -10000");
+		assert!(multiply(integer(0), integer(0)), "0 * 0");
+		assert!(multiply(integer(10000), integer(10000)), "10000 * 10000");
+		assert!(multiply(integer(-10000), integer(-10000)), "-10000 * -10000");
 
-		assert_eq!(format(divide(integer(0), integer(0))), "0 / 0");
-		assert_eq!(format(divide(integer(10000), integer(10000))), "10000 / 10000");
-		assert_eq!(format(divide(integer(-10000), integer(-10000))), "-10000 / -10000");
+		assert!(divide(integer(0), integer(0)), "0 / 0");
+		assert!(divide(integer(10000), integer(10000)), "10000 / 10000");
+		assert!(divide(integer(-10000), integer(-10000)), "-10000 / -10000");
 
-		assert_eq!(format(modulo(integer(0), integer(0))), "0 % 0");
-		assert_eq!(format(modulo(integer(10000), integer(10000))), "10000 % 10000");
-		assert_eq!(format(modulo(integer(-10000), integer(-10000))), "-10000 % -10000");
+		assert!(modulo(integer(0), integer(0)), "0 % 0");
+		assert!(modulo(integer(10000), integer(10000)), "10000 % 10000");
+		assert!(modulo(integer(-10000), integer(-10000)), "-10000 % -10000");
 
-		assert_eq!(format(add(integer(0), integer(0))), "0 + 0");
-		assert_eq!(format(add(integer(10000), integer(10000))), "10000 + 10000");
-		assert_eq!(format(add(integer(-10000), integer(-10000))), "-10000 + -10000");
+		assert!(add(integer(0), integer(0)), "0 + 0");
+		assert!(add(integer(10000), integer(10000)), "10000 + 10000");
+		assert!(add(integer(-10000), integer(-10000)), "-10000 + -10000");
 
-		assert_eq!(format(subtract(integer(0), integer(0))), "0 - 0");
-		assert_eq!(format(subtract(integer(10000), integer(10000))), "10000 - 10000");
-		assert_eq!(format(subtract(integer(-10000), integer(-10000))), "-10000 - -10000");
+		assert!(subtract(integer(0), integer(0)), "0 - 0");
+		assert!(subtract(integer(10000), integer(10000)), "10000 - 10000");
+		assert!(subtract(integer(-10000), integer(-10000)), "-10000 - -10000");
 	}
 
 	#[test]
 	fn format_combination_string_and_lower()
 	{
-		assert_eq!(format(
-			function("f", vec![string(""), string(""), string("")])),
-			"f(\"\", \"\", \"\")");
-		assert_eq!(format(
-			function("f", vec![string("test 123"), string("test 123"), string("test 123")])),
+		assert!(function("f", vec![string(""), string(""), string("")]), "f(\"\", \"\", \"\")");
+		assert!(function("f", vec![string("test 123"), string("test 123"), string("test 123")]),
 			"f(\"test 123\", \"test 123\", \"test 123\")");
-		assert_eq!(format(
-			function("f", vec![string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t"),
-				string("\\a\nb🙂c\t")])),
+		assert!(function("f", vec![string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t"),
+				string("\\a\nb🙂c\t")]),
 			"f(\"\\\\a\\nb🙂c\\t\", \"\\\\a\\nb🙂c\\t\", \"\\\\a\\nb🙂c\\t\")");
 
-		assert_eq!(format(absolute_value(string(""))), "|\"\"|");
-		assert_eq!(format(absolute_value(string("test 123"))), "|\"test 123\"|");
-		assert_eq!(format(absolute_value(string("\\a\nb🙂c\t"))), "|\"\\\\a\\nb🙂c\\t\"|");
+		assert!(absolute_value(string("")), "|\"\"|");
+		assert!(absolute_value(string("test 123")), "|\"test 123\"|");
+		assert!(absolute_value(string("\\a\nb🙂c\t")), "|\"\\\\a\\nb🙂c\\t\"|");
 
-		assert_eq!(format(negative(string(""))), "-\"\"");
-		assert_eq!(format(negative(string("test 123"))), "-\"test 123\"");
-		assert_eq!(format(negative(string("\\a\nb🙂c\t"))), "-\"\\\\a\\nb🙂c\\t\"");
+		assert!(negative(string("")), "-\"\"");
+		assert!(negative(string("test 123")), "-\"test 123\"");
+		assert!(negative(string("\\a\nb🙂c\t")), "-\"\\\\a\\nb🙂c\\t\"");
 
-		assert_eq!(format(exponentiate(string(""), string(""))), "\"\" ** \"\"");
-		assert_eq!(format(
-			exponentiate(string("test 123"), string("test 123"))),
+		assert!(exponentiate(string(""), string("")), "\"\" ** \"\"");
+		assert!(exponentiate(string("test 123"), string("test 123")),
 			"\"test 123\" ** \"test 123\"");
-		assert_eq!(format(
-			exponentiate(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t"))),
+		assert!(exponentiate(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t")),
 			"\"\\\\a\\nb🙂c\\t\" ** \"\\\\a\\nb🙂c\\t\"");
 
-		assert_eq!(format(multiply(string(""), string(""))), "\"\" * \"\"");
-		assert_eq!(format(
-			multiply(string("test 123"), string("test 123"))),
-			"\"test 123\" * \"test 123\"");
-		assert_eq!(format(
-			multiply(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t"))),
+		assert!(multiply(string(""), string("")), "\"\" * \"\"");
+		assert!(multiply(string("test 123"), string("test 123")), "\"test 123\" * \"test 123\"");
+		assert!(multiply(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t")),
 			"\"\\\\a\\nb🙂c\\t\" * \"\\\\a\\nb🙂c\\t\"");
 
-		assert_eq!(format(divide(string(""), string(""))), "\"\" / \"\"");
-		assert_eq!(format(
-			divide(string("test 123"), string("test 123"))),
-			"\"test 123\" / \"test 123\"");
-		assert_eq!(format(
-			divide(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t"))),
+		assert!(divide(string(""), string("")), "\"\" / \"\"");
+		assert!(divide(string("test 123"), string("test 123")), "\"test 123\" / \"test 123\"");
+		assert!(divide(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t")),
 			"\"\\\\a\\nb🙂c\\t\" / \"\\\\a\\nb🙂c\\t\"");
 
-		assert_eq!(format(modulo(string(""), string(""))), "\"\" % \"\"");
-		assert_eq!(format(
-			modulo(string("test 123"), string("test 123"))),
-			"\"test 123\" % \"test 123\"");
-		assert_eq!(format(
-			modulo(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t"))),
+		assert!(modulo(string(""), string("")), "\"\" % \"\"");
+		assert!(modulo(string("test 123"), string("test 123")), "\"test 123\" % \"test 123\"");
+		assert!(modulo(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t")),
 			"\"\\\\a\\nb🙂c\\t\" % \"\\\\a\\nb🙂c\\t\"");
 
-		assert_eq!(format(add(string(""), string(""))), "\"\" + \"\"");
-		assert_eq!(format(
-			add(string("test 123"), string("test 123"))),
-			"\"test 123\" + \"test 123\"");
-		assert_eq!(format(
-			add(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t"))),
+		assert!(add(string(""), string("")), "\"\" + \"\"");
+		assert!(add(string("test 123"), string("test 123")), "\"test 123\" + \"test 123\"");
+		assert!(add(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t")),
 			"\"\\\\a\\nb🙂c\\t\" + \"\\\\a\\nb🙂c\\t\"");
 
-		assert_eq!(format(subtract(string(""), string(""))), "\"\" - \"\"");
-		assert_eq!(format(
-			subtract(string("test 123"), string("test 123"))),
-			"\"test 123\" - \"test 123\"");
-		assert_eq!(format(
-			subtract(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t"))),
+		assert!(subtract(string(""), string("")), "\"\" - \"\"");
+		assert!(subtract(string("test 123"), string("test 123")), "\"test 123\" - \"test 123\"");
+		assert!(subtract(string("\\a\nb🙂c\t"), string("\\a\nb🙂c\t")),
 			"\"\\\\a\\nb🙂c\\t\" - \"\\\\a\\nb🙂c\\t\"");
 	}
 
 	#[test]
 	fn format_combination_variable_and_lower()
 	{
-		assert_eq!(format(variable("X")), "X");
-		assert_eq!(format(variable("Variable")), "Variable");
+		assert!(variable("X"), "X");
+		assert!(variable("Variable"), "Variable");
 
-		assert_eq!(format(absolute_value(variable("X"))), "|X|");
-		assert_eq!(format(absolute_value(variable("Variable"))), "|Variable|");
+		assert!(absolute_value(variable("X")), "|X|");
+		assert!(absolute_value(variable("Variable")), "|Variable|");
 
-		assert_eq!(format(negative(variable("X"))), "-X");
-		assert_eq!(format(negative(variable("Variable"))), "-Variable");
+		assert!(negative(variable("X")), "-X");
+		assert!(negative(variable("Variable")), "-Variable");
 
-		assert_eq!(format(exponentiate(variable("X"), variable("X"))), "X ** X");
-		assert_eq!(format(
-			exponentiate(variable("Variable"), variable("Variable"))),
-			"Variable ** Variable");
+		assert!(exponentiate(variable("X"), variable("X")), "X ** X");
+		assert!(exponentiate(variable("Variable"), variable("Variable")), "Variable ** Variable");
 
-		assert_eq!(format(multiply(variable("X"), variable("X"))), "X * X");
-		assert_eq!(format(
-			multiply(variable("Variable"), variable("Variable"))),
-			"Variable * Variable");
+		assert!(multiply(variable("X"), variable("X")), "X * X");
+		assert!(multiply(variable("Variable"), variable("Variable")), "Variable * Variable");
 
-		assert_eq!(format(divide(variable("X"), variable("X"))), "X / X");
-		assert_eq!(format(
-			divide(variable("Variable"), variable("Variable"))), "Variable / Variable");
+		assert!(divide(variable("X"), variable("X")), "X / X");
+		assert!(divide(variable("Variable"), variable("Variable")), "Variable / Variable");
 
-		assert_eq!(format(modulo(variable("X"), variable("X"))), "X % X");
-		assert_eq!(format(
-			modulo(variable("Variable"), variable("Variable"))), "Variable % Variable");
+		assert!(modulo(variable("X"), variable("X")), "X % X");
+		assert!(modulo(variable("Variable"), variable("Variable")), "Variable % Variable");
 
-		assert_eq!(format(add(variable("X"), variable("X"))), "X + X");
-		assert_eq!(format(
-			add(variable("Variable"), variable("Variable"))), "Variable + Variable");
+		assert!(add(variable("X"), variable("X")), "X + X");
+		assert!(add(variable("Variable"), variable("Variable")), "Variable + Variable");
 
-		assert_eq!(format(subtract(variable("X"), variable("X"))), "X - X");
-		assert_eq!(format(
-			subtract(variable("Variable"), variable("Variable"))), "Variable - Variable");
+		assert!(subtract(variable("X"), variable("X")), "X - X");
+		assert!(subtract(variable("Variable"), variable("Variable")), "Variable - Variable");
 	}
 
 	#[test]
@@ -711,332 +677,228 @@ pub(crate) mod tests
 		let f3 = || function("f", vec![constant("a")]);
 		let f4 = || function("function", vec![constant("a"), constant("b"), constant("c")]);
 
-		assert_eq!(format(absolute_value(f1())), "|a|");
-		assert_eq!(format(absolute_value(f2())), "|constant|");
-		assert_eq!(format(absolute_value(f3())), "|f(a)|");
-		assert_eq!(format(absolute_value(f4())), "|function(a, b, c)|");
-		assert_eq!(format(function("f", vec![absolute_value(constant("a"))])), "f(|a|)");
-		assert_eq!(format(
-			function("f", vec![absolute_value(constant("a")), absolute_value(constant("b")),
-				absolute_value(constant("c"))])),
+		assert!(absolute_value(f1()), "|a|");
+		assert!(absolute_value(f2()), "|constant|");
+		assert!(absolute_value(f3()), "|f(a)|");
+		assert!(absolute_value(f4()), "|function(a, b, c)|");
+		assert!(function("f", vec![absolute_value(constant("a"))]), "f(|a|)");
+		assert!(function("f", vec![absolute_value(constant("a")), absolute_value(constant("b")),
+			absolute_value(constant("c"))]),
 			"f(|a|, |b|, |c|)");
 
-		assert_eq!(format(negative(f1())), "-a");
-		assert_eq!(format(negative(f2())), "-constant");
-		assert_eq!(format(negative(f3())), "-f(a)");
-		assert_eq!(format(negative(f4())), "-function(a, b, c)");
-		assert_eq!(format(function("f", vec![negative(constant("a"))])), "f(-a)");
-		assert_eq!(format(
-			function("f", vec![negative(constant("a")), negative(constant("b")),
-				negative(constant("c"))])),
+		assert!(negative(f1()), "-a");
+		assert!(negative(f2()), "-constant");
+		assert!(negative(f3()), "-f(a)");
+		assert!(negative(f4()), "-function(a, b, c)");
+		assert!(function("f", vec![negative(constant("a"))]), "f(-a)");
+		assert!(function("f", vec![negative(constant("a")), negative(constant("b")),
+			negative(constant("c"))]),
 			"f(-a, -b, -c)");
 
-		assert_eq!(format(exponentiate(f1(), f1())), "a ** a");
-		assert_eq!(format(exponentiate(f2(), f2())), "constant ** constant");
-		assert_eq!(format(exponentiate(f3(), f3())), "f(a) ** f(a)");
-		assert_eq!(format(exponentiate(f4(), f4())), "function(a, b, c) ** function(a, b, c)");
-		assert_eq!(format(
-			function("f", vec![exponentiate(constant("a"), constant("b"))])),
-			"f(a ** b)");
-		assert_eq!(format(
-			function("f", vec![exponentiate(constant("a"), constant("b")),
-				exponentiate(constant("c"), constant("d")),
-				exponentiate(constant("e"), constant("f"))])),
+		assert!(exponentiate(f1(), f1()), "a ** a");
+		assert!(exponentiate(f2(), f2()), "constant ** constant");
+		assert!(exponentiate(f3(), f3()), "f(a) ** f(a)");
+		assert!(exponentiate(f4(), f4()), "function(a, b, c) ** function(a, b, c)");
+		assert!(function("f", vec![exponentiate(constant("a"), constant("b"))]), "f(a ** b)");
+		assert!(function("f", vec![exponentiate(constant("a"), constant("b")),
+			exponentiate(constant("c"), constant("d")),
+			exponentiate(constant("e"), constant("f"))]),
 			"f(a ** b, c ** d, e ** f)");
 
-		assert_eq!(format(multiply(f1(), f1())), "a * a");
-		assert_eq!(format(multiply(f2(), f2())), "constant * constant");
-		assert_eq!(format(multiply(f3(), f3())), "f(a) * f(a)");
-		assert_eq!(format(multiply(f4(), f4())), "function(a, b, c) * function(a, b, c)");
-		assert_eq!(format(function("f", vec![multiply(constant("a"), constant("b"))])), "f(a * b)");
-		assert_eq!(format(
-			function("f", vec![multiply(constant("a"), constant("b")),
-				multiply(constant("c"), constant("d")), multiply(constant("e"), constant("f"))])),
+		assert!(multiply(f1(), f1()), "a * a");
+		assert!(multiply(f2(), f2()), "constant * constant");
+		assert!(multiply(f3(), f3()), "f(a) * f(a)");
+		assert!(multiply(f4(), f4()), "function(a, b, c) * function(a, b, c)");
+		assert!(function("f", vec![multiply(constant("a"), constant("b"))]), "f(a * b)");
+		assert!(function("f", vec![multiply(constant("a"), constant("b")),
+			multiply(constant("c"), constant("d")), multiply(constant("e"), constant("f"))]),
 			"f(a * b, c * d, e * f)");
 
-		assert_eq!(format(divide(f1(), f1())), "a / a");
-		assert_eq!(format(divide(f2(), f2())), "constant / constant");
-		assert_eq!(format(divide(f3(), f3())), "f(a) / f(a)");
-		assert_eq!(format(divide(f4(), f4())), "function(a, b, c) / function(a, b, c)");
-		assert_eq!(format(function("f", vec![divide(constant("a"), constant("b"))])), "f(a / b)");
-		assert_eq!(format(
-			function("f", vec![divide(constant("a"), constant("b")),
-				divide(constant("c"), constant("d")), divide(constant("e"), constant("f"))])),
+		assert!(divide(f1(), f1()), "a / a");
+		assert!(divide(f2(), f2()), "constant / constant");
+		assert!(divide(f3(), f3()), "f(a) / f(a)");
+		assert!(divide(f4(), f4()), "function(a, b, c) / function(a, b, c)");
+		assert!(function("f", vec![divide(constant("a"), constant("b"))]), "f(a / b)");
+		assert!(function("f", vec![divide(constant("a"), constant("b")),
+			divide(constant("c"), constant("d")), divide(constant("e"), constant("f"))]),
 			"f(a / b, c / d, e / f)");
 
-		assert_eq!(format(modulo(f1(), f1())), "a % a");
-		assert_eq!(format(modulo(f2(), f2())), "constant % constant");
-		assert_eq!(format(modulo(f3(), f3())), "f(a) % f(a)");
-		assert_eq!(format(modulo(f4(), f4())), "function(a, b, c) % function(a, b, c)");
-		assert_eq!(format(function("f", vec![modulo(constant("a"), constant("b"))])), "f(a % b)");
-		assert_eq!(format(
-			function("f", vec![modulo(constant("a"), constant("b")),
-				modulo(constant("c"), constant("d")), modulo(constant("e"), constant("f"))])),
+		assert!(modulo(f1(), f1()), "a % a");
+		assert!(modulo(f2(), f2()), "constant % constant");
+		assert!(modulo(f3(), f3()), "f(a) % f(a)");
+		assert!(modulo(f4(), f4()), "function(a, b, c) % function(a, b, c)");
+		assert!(function("f", vec![modulo(constant("a"), constant("b"))]), "f(a % b)");
+		assert!(function("f", vec![modulo(constant("a"), constant("b")),
+			modulo(constant("c"), constant("d")), modulo(constant("e"), constant("f"))]),
 			"f(a % b, c % d, e % f)");
 
-		assert_eq!(format(add(f1(), f1())), "a + a");
-		assert_eq!(format(add(f2(), f2())), "constant + constant");
-		assert_eq!(format(add(f3(), f3())), "f(a) + f(a)");
-		assert_eq!(format(add(f4(), f4())), "function(a, b, c) + function(a, b, c)");
-		assert_eq!(format(function("f", vec![add(constant("a"), constant("b"))])), "f(a + b)");
-		assert_eq!(format(
-			function("f", vec![add(constant("a"), constant("b")),
-				add(constant("c"), constant("d")), add(constant("e"), constant("f"))])),
+		assert!(add(f1(), f1()), "a + a");
+		assert!(add(f2(), f2()), "constant + constant");
+		assert!(add(f3(), f3()), "f(a) + f(a)");
+		assert!(add(f4(), f4()), "function(a, b, c) + function(a, b, c)");
+		assert!(function("f", vec![add(constant("a"), constant("b"))]), "f(a + b)");
+		assert!(function("f", vec![add(constant("a"), constant("b")),
+			add(constant("c"), constant("d")), add(constant("e"), constant("f"))]),
 			"f(a + b, c + d, e + f)");
 
-		assert_eq!(format(subtract(f1(), f1())), "a - a");
-		assert_eq!(format(subtract(f2(), f2())), "constant - constant");
-		assert_eq!(format(subtract(f3(), f3())), "f(a) - f(a)");
-		assert_eq!(format(subtract(f4(), f4())), "function(a, b, c) - function(a, b, c)");
-		assert_eq!(format(function("f", vec![subtract(constant("a"), constant("b"))])), "f(a - b)");
-		assert_eq!(format(
-			function("f", vec![subtract(constant("a"), constant("b")),
-				subtract(constant("c"), constant("d")), subtract(constant("e"), constant("f"))])),
+		assert!(subtract(f1(), f1()), "a - a");
+		assert!(subtract(f2(), f2()), "constant - constant");
+		assert!(subtract(f3(), f3()), "f(a) - f(a)");
+		assert!(subtract(f4(), f4()), "function(a, b, c) - function(a, b, c)");
+		assert!(function("f", vec![subtract(constant("a"), constant("b"))]), "f(a - b)");
+		assert!(function("f", vec![subtract(constant("a"), constant("b")),
+			subtract(constant("c"), constant("d")), subtract(constant("e"), constant("f"))]),
 			"f(a - b, c - d, e - f)");
 	}
 
 	#[test]
 	fn format_combination_absolute_value_and_lower()
 	{
-		assert_eq!(format(absolute_value(absolute_value(constant("a")))), "||a||");
-		assert_eq!(format(absolute_value(negative(constant("a")))), "|-a|");
-		assert_eq!(format(negative(absolute_value(constant("a")))), "-|a|");
-		assert_eq!(format(absolute_value(add(constant("a"), constant("b")))), "|a + b|");
-		assert_eq!(format(
-			add(absolute_value(constant("a")), absolute_value(constant("b")))),
-			"|a| + |b|");
-		assert_eq!(format(absolute_value(subtract(constant("a"), constant("b")))), "|a - b|");
-		assert_eq!(format(
-			subtract(absolute_value(constant("a")), absolute_value(constant("b")))),
+		assert!(absolute_value(absolute_value(constant("a"))), "||a||");
+		assert!(absolute_value(negative(constant("a"))), "|-a|");
+		assert!(negative(absolute_value(constant("a"))), "-|a|");
+		assert!(absolute_value(add(constant("a"), constant("b"))), "|a + b|");
+		assert!(add(absolute_value(constant("a")), absolute_value(constant("b"))), "|a| + |b|");
+		assert!(absolute_value(subtract(constant("a"), constant("b"))), "|a - b|");
+		assert!(subtract(absolute_value(constant("a")), absolute_value(constant("b"))),
 			"|a| - |b|");
-		assert_eq!(format(absolute_value(multiply(constant("a"), constant("b")))), "|a * b|");
-		assert_eq!(format(
-			multiply(absolute_value(constant("a")), absolute_value(constant("b")))),
+		assert!(absolute_value(multiply(constant("a"), constant("b"))), "|a * b|");
+		assert!(multiply(absolute_value(constant("a")), absolute_value(constant("b"))),
 			"|a| * |b|");
-		assert_eq!(format(absolute_value(divide(constant("a"), constant("b")))), "|a / b|");
-		assert_eq!(format(
-			divide(absolute_value(constant("a")), absolute_value(constant("b")))),
-			"|a| / |b|");
-		assert_eq!(format(absolute_value(modulo(constant("a"), constant("b")))), "|a % b|");
-		assert_eq!(format(
-			modulo(absolute_value(constant("a")), absolute_value(constant("b")))),
-			"|a| % |b|");
-		assert_eq!(format(absolute_value(exponentiate(constant("a"), constant("b")))), "|a ** b|");
-		assert_eq!(format(
-			exponentiate(absolute_value(constant("a")), absolute_value(constant("b")))),
+		assert!(absolute_value(divide(constant("a"), constant("b"))), "|a / b|");
+		assert!(
+			divide(absolute_value(constant("a")), absolute_value(constant("b"))), "|a| / |b|");
+		assert!(absolute_value(modulo(constant("a"), constant("b"))), "|a % b|");
+		assert!(modulo(absolute_value(constant("a")), absolute_value(constant("b"))), "|a| % |b|");
+		assert!(absolute_value(exponentiate(constant("a"), constant("b"))), "|a ** b|");
+		assert!(exponentiate(absolute_value(constant("a")), absolute_value(constant("b"))),
 			"|a| ** |b|");
 	}
 
 	#[test]
 	fn format_combination_negative_and_lower()
 	{
-		assert_eq!(format(negative(negative(constant("a")))), "--a");
-		assert_eq!(format(add(negative(constant("a")), negative(constant("b")))), "-a + -b");
-		assert_eq!(format(negative(add(constant("a"), constant("b")))), "-(a + b)");
-		assert_eq!(format(subtract(negative(constant("a")), negative(constant("b")))), "-a - -b");
-		assert_eq!(format(negative(subtract(constant("a"), constant("b")))), "-(a - b)");
-		assert_eq!(format(multiply(negative(constant("a")), negative(constant("b")))), "-a * -b");
-		assert_eq!(format(negative(multiply(constant("a"), constant("b")))), "-(a * b)");
-		assert_eq!(format(divide(negative(constant("a")), negative(constant("b")))), "-a / -b");
-		assert_eq!(format(negative(divide(constant("a"), constant("b")))), "-(a / b)");
-		assert_eq!(format(modulo(negative(constant("a")), negative(constant("b")))), "-a % -b");
-		assert_eq!(format(negative(modulo(constant("a"), constant("b")))), "-(a % b)");
-		assert_eq!(format(exponentiate(negative(constant("a")), negative(constant("b")))), "-a ** -b");
-		assert_eq!(format(negative(exponentiate(constant("a"), constant("b")))), "-(a ** b)");
+		assert!(negative(negative(constant("a"))), "--a");
+		assert!(add(negative(constant("a")), negative(constant("b"))), "-a + -b");
+		assert!(negative(add(constant("a"), constant("b"))), "-(a + b)");
+		assert!(subtract(negative(constant("a")), negative(constant("b"))), "-a - -b");
+		assert!(negative(subtract(constant("a"), constant("b"))), "-(a - b)");
+		assert!(multiply(negative(constant("a")), negative(constant("b"))), "-a * -b");
+		assert!(negative(multiply(constant("a"), constant("b"))), "-(a * b)");
+		assert!(divide(negative(constant("a")), negative(constant("b"))), "-a / -b");
+		assert!(negative(divide(constant("a"), constant("b"))), "-(a / b)");
+		assert!(modulo(negative(constant("a")), negative(constant("b"))), "-a % -b");
+		assert!(negative(modulo(constant("a"), constant("b"))), "-(a % b)");
+		assert!(exponentiate(negative(constant("a")), negative(constant("b"))), "-a ** -b");
+		assert!(negative(exponentiate(constant("a"), constant("b"))), "-(a ** b)");
 	}
 
 	#[test]
 	fn format_combination_exponentiate_and_lower()
 	{
-		assert_eq!(format(
-			exponentiate(
-				exponentiate(constant("a"), constant("b")),
-				exponentiate(constant("c"), constant("d")))),
+		assert!(exponentiate(exponentiate(constant("a"), constant("b")),
+			exponentiate(constant("c"), constant("d"))),
 			"(a ** b) ** c ** d");
-		assert_eq!(format(
-			exponentiate(
-				multiply(constant("a"), constant("b")),
-				multiply(constant("c"), constant("d")))),
+		assert!(exponentiate(multiply(constant("a"), constant("b")),
+			multiply(constant("c"), constant("d"))),
 			"(a * b) ** (c * d)");
-		assert_eq!(format(
-			multiply(
-				exponentiate(constant("a"), constant("b")),
-				exponentiate(constant("c"), constant("d")))),
+		assert!(multiply(exponentiate(constant("a"), constant("b")),
+			exponentiate(constant("c"), constant("d"))),
 			"a ** b * c ** d");
-		assert_eq!(format(
-			exponentiate(
-				divide(constant("a"), constant("b")),
-				divide(constant("c"), constant("d")))),
+		assert!(exponentiate(divide(constant("a"), constant("b")),
+			divide(constant("c"), constant("d"))),
 			"(a / b) ** (c / d)");
-		assert_eq!(format(
-			divide(
-				exponentiate(constant("a"), constant("b")),
-				exponentiate(constant("c"), constant("d")))),
+		assert!(divide(exponentiate(constant("a"), constant("b")),
+			exponentiate(constant("c"), constant("d"))),
 			"a ** b / c ** d");
-		assert_eq!(format(
-			exponentiate(
-				modulo(constant("a"), constant("b")),
-				modulo(constant("c"), constant("d")))),
+		assert!(exponentiate(modulo(constant("a"), constant("b")),
+			modulo(constant("c"), constant("d"))),
 			"(a % b) ** (c % d)");
-		assert_eq!(format(
-			modulo(
-				exponentiate(constant("a"), constant("b")),
-				exponentiate(constant("c"), constant("d")))),
+		assert!(modulo(exponentiate(constant("a"), constant("b")),
+			exponentiate(constant("c"), constant("d"))),
 			"a ** b % c ** d");
-		assert_eq!(format(
-			exponentiate(
-				add(constant("a"), constant("b")),
-				add(constant("c"), constant("d")))),
+		assert!(exponentiate(add(constant("a"), constant("b")), add(constant("c"), constant("d"))),
 			"(a + b) ** (c + d)");
-		assert_eq!(format(
-			add(
-				exponentiate(constant("a"), constant("b")),
-				exponentiate(constant("c"), constant("d")))),
+		assert!(add(exponentiate(constant("a"), constant("b")),
+			exponentiate(constant("c"), constant("d"))),
 			"a ** b + c ** d");
-		assert_eq!(format(
-			exponentiate(
-				subtract(constant("a"), constant("b")),
-				subtract(constant("c"), constant("d")))),
+		assert!(exponentiate(subtract(constant("a"), constant("b")),
+			subtract(constant("c"), constant("d"))),
 			"(a - b) ** (c - d)");
-		assert_eq!(format(
-			subtract(
-				exponentiate(constant("a"), constant("b")),
-				exponentiate(constant("c"), constant("d")))),
+		assert!(subtract(exponentiate(constant("a"), constant("b")),
+			exponentiate(constant("c"), constant("d"))),
 			"a ** b - c ** d");
 	}
 
 	#[test]
 	fn format_combination_multiplicative_binary_operations_and_lower()
 	{
-		assert_eq!(format(
-			multiply(
-				multiply(constant("a"), constant("b")),
-				multiply(constant("c"), constant("d")))),
+		assert!(multiply(multiply(constant("a"), constant("b")),
+			multiply(constant("c"), constant("d"))),
 			"a * b * c * d");
-		assert_eq!(format(
-			multiply(
-				divide(constant("a"), constant("b")),
-				divide(constant("c"), constant("d")))),
+		assert!(multiply(divide(constant("a"), constant("b")),
+			divide(constant("c"), constant("d"))),
 			"a / b * c / d");
-		assert_eq!(format(
-			multiply(
-				modulo(constant("a"), constant("b")),
-				modulo(constant("c"), constant("d")))),
+		assert!(multiply(modulo(constant("a"), constant("b")),
+			modulo(constant("c"), constant("d"))),
 			"a % b * (c % d)");
-		assert_eq!(format(
-			divide(
-				multiply(constant("a"), constant("b")),
-				multiply(constant("c"), constant("d")))),
+		assert!(divide(multiply(constant("a"), constant("b")),
+			multiply(constant("c"), constant("d"))),
 			"a * b / (c * d)");
-		assert_eq!(format(
-			divide(
-				divide(constant("a"), constant("b")),
-				divide(constant("c"), constant("d")))),
+		assert!(divide(divide(constant("a"), constant("b")), divide(constant("c"), constant("d"))),
 			"a / b / (c / d)");
-		assert_eq!(format(
-			divide(
-				modulo(constant("a"), constant("b")),
-				modulo(constant("c"), constant("d")))),
+		assert!(divide(modulo(constant("a"), constant("b")), modulo(constant("c"), constant("d"))),
 			"a % b / (c % d)");
-		assert_eq!(format(
-			modulo(
-				multiply(constant("a"), constant("b")),
-				multiply(constant("c"), constant("d")))),
+		assert!(modulo(multiply(constant("a"), constant("b")),
+			multiply(constant("c"), constant("d"))),
 			"a * b % (c * d)");
-		assert_eq!(format(
-			modulo(
-				divide(constant("a"), constant("b")),
-				divide(constant("c"), constant("d")))),
+		assert!(modulo(divide(constant("a"), constant("b")), divide(constant("c"), constant("d"))),
 			"a / b % (c / d)");
-		assert_eq!(format(
-			modulo(
-				modulo(constant("a"), constant("b")),
-				modulo(constant("c"), constant("d")))),
+		assert!(modulo(modulo(constant("a"), constant("b")), modulo(constant("c"), constant("d"))),
 			"a % b % (c % d)");
-		assert_eq!(format(
-			multiply(
-				add(constant("a"), constant("b")),
-				add(constant("c"), constant("d")))),
+		assert!(multiply(add(constant("a"), constant("b")), add(constant("c"), constant("d"))),
 			"(a + b) * (c + d)");
-		assert_eq!(format(
-			add(
-				multiply(constant("a"), constant("b")),
-				multiply(constant("c"), constant("d")))),
+		assert!(add(multiply(constant("a"), constant("b")), multiply(constant("c"), constant("d"))),
 			"a * b + c * d");
-		assert_eq!(format(
-			multiply(
-				subtract(constant("a"), constant("b")),
-				subtract(constant("c"), constant("d")))),
+		assert!(multiply(subtract(constant("a"), constant("b")),
+			subtract(constant("c"), constant("d"))),
 			"(a - b) * (c - d)");
-		assert_eq!(format(
-			subtract(
-				multiply(constant("a"), constant("b")),
-				multiply(constant("c"), constant("d")))),
+		assert!(subtract(multiply(constant("a"), constant("b")),
+			multiply(constant("c"), constant("d"))),
 			"a * b - c * d");
-		assert_eq!(format(
-			divide(
-				add(constant("a"), constant("b")),
-				add(constant("c"), constant("d")))),
+		assert!(divide(add(constant("a"), constant("b")), add(constant("c"), constant("d"))),
 			"(a + b) / (c + d)");
-		assert_eq!(format(
-			add(
-				divide(constant("a"), constant("b")),
-				divide(constant("c"), constant("d")))),
+		assert!(add(divide(constant("a"), constant("b")), divide(constant("c"), constant("d"))),
 			"a / b + c / d");
-		assert_eq!(format(
-			divide(
-				subtract(constant("a"), constant("b")),
-				subtract(constant("c"), constant("d")))),
+		assert!(divide(subtract(constant("a"), constant("b")),
+			subtract(constant("c"), constant("d"))),
 			"(a - b) / (c - d)");
-		assert_eq!(format(
-			subtract(
-				divide(constant("a"), constant("b")),
-				divide(constant("c"), constant("d")))),
+		assert!(subtract(divide(constant("a"), constant("b")),
+			divide(constant("c"), constant("d"))),
 			"a / b - c / d");
-		assert_eq!(format(
-			modulo(
-				add(constant("a"), constant("b")),
-				add(constant("c"), constant("d")))),
+		assert!(modulo(add(constant("a"), constant("b")), add(constant("c"), constant("d"))),
 			"(a + b) % (c + d)");
-		assert_eq!(format(
-			add(
-				modulo(constant("a"), constant("b")),
-				modulo(constant("c"), constant("d")))),
+		assert!(add(modulo(constant("a"), constant("b")), modulo(constant("c"), constant("d"))),
 			"a % b + c % d");
-		assert_eq!(format(
-			modulo(
-				subtract(constant("a"), constant("b")),
-				subtract(constant("c"), constant("d")))),
+		assert!(modulo(subtract(constant("a"), constant("b")),
+			subtract(constant("c"), constant("d"))),
 			"(a - b) % (c - d)");
-		assert_eq!(format(
-			subtract(
-				modulo(constant("a"), constant("b")),
-				modulo(constant("c"), constant("d")))),
+		assert!(subtract(modulo(constant("a"), constant("b")),
+			modulo(constant("c"), constant("d"))),
 			"a % b - c % d");
 	}
 
 	#[test]
 	fn format_combination_additive_binary_operations_and_lower()
 	{
-		assert_eq!(format(
-			add(
-				add(constant("a"), constant("b")),
-				add(constant("c"), constant("d")))),
+		assert!(add(add(constant("a"), constant("b")), add(constant("c"), constant("d"))),
 			"a + b + c + d");
-		assert_eq!(format(
-			add(
-				subtract(constant("a"), constant("b")),
-				subtract(constant("c"), constant("d")))),
+		assert!(add(subtract(constant("a"), constant("b")), subtract(constant("c"), constant("d"))),
 			"a - b + c - d");
-		assert_eq!(format(
-			subtract(
-				add(constant("a"), constant("b")),
-				add(constant("c"), constant("d")))),
+		assert!(subtract(add(constant("a"), constant("b")), add(constant("c"), constant("d"))),
 			"a + b - (c + d)");
-		assert_eq!(format(
-			subtract(
-				subtract(constant("a"), constant("b")),
-				subtract(constant("c"), constant("d")))),
+		assert!(subtract(subtract(constant("a"), constant("b")),
+			subtract(constant("c"), constant("d"))),
 			"a - b - (c - d)");
 	}
 }