diff --git a/tests/src/App/Expression.cpp b/tests/src/App/Expression.cpp
index 2072796c32..8a7c1a50fb 100644
--- a/tests/src/App/Expression.cpp
+++ b/tests/src/App/Expression.cpp
@@ -1,25 +1,52 @@
 #include "gtest/gtest.h"
 
+#include "App/ExpressionParser.h"
 #include "App/ExpressionTokenizer.h"
 
+// clang-format off
 TEST(Expression, tokenize)
 {
     EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8(""), 10), QString());
     // 0.0000 deg-
     EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8("0.00000 \xC2\xB0-"), 10), QString());
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8("0.00000 \xC2\xB0-s"), 11), QString("s"));
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8("0.00000 \xC2\xB0-ss"), 12), QString("ss"));
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8("0.00000 \xC2\xB0-s"), 11), QString::fromLatin1("s"));
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8("0.00000 \xC2\xB0-ss"), 12), QString::fromLatin1("ss"));
     EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8("0.00000 deg"), 5), QString());
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8("0.00000 deg"), 11), QString("deg"));
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromUtf8("0.00000 deg"), 11), QString::fromLatin1("deg"));
 }
 
 TEST(Expression, tokenizePi)
 {
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString("p"), 1), QString("p"));
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString("pi"), 2), QString());
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString("pi "), 3), QString());
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString("pi r"), 4), QString("r"));
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString("pi ra"), 5), QString("ra"));
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString("pi rad"), 6), QString("rad"));
-    EXPECT_EQ(App::ExpressionTokenizer().perform(QString("pi rad"), 2), QString());
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromLatin1("p"), 1), QString::fromLatin1("p"));
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromLatin1("pi"), 2), QString());
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromLatin1("pi "), 3), QString());
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromLatin1("pi r"), 4), QString::fromLatin1("r"));
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromLatin1("pi ra"), 5), QString::fromLatin1("ra"));
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromLatin1("pi rad"), 6), QString::fromLatin1("rad"));
+    EXPECT_EQ(App::ExpressionTokenizer().perform(QString::fromLatin1("pi rad"), 2), QString());
 }
+
+TEST(Expression, toString)
+{
+    App::UnitExpression expr{nullptr, Base::Quantity{}, "pi rad"};
+    EXPECT_EQ(expr.toString(), "pi rad");
+}
+
+TEST(Expression, test_pi_rad)
+{
+    auto constant = std::make_unique<App::ConstantExpression>(nullptr, "pi");
+    auto unit = std::make_unique<App::UnitExpression>(nullptr, Base::Quantity{}, "rad");
+    auto op = std::make_unique<App::OperatorExpression>(nullptr, constant.get(), App::OperatorExpression::UNIT, unit.get());
+    EXPECT_EQ(op->toString(), "pi rad");
+    op.release();
+}
+
+TEST(Expression, test_e_rad)
+{
+    auto constant = std::make_unique<App::ConstantExpression>(nullptr, "e");
+    auto unit = std::make_unique<App::UnitExpression>(nullptr, Base::Quantity{}, "rad");
+    auto op = std::make_unique<App::OperatorExpression>(nullptr, constant.get(), App::OperatorExpression::UNIT, unit.get());
+    EXPECT_EQ(op->toString(), "e rad");
+    op.release();
+}
+// clang-format on