compleated all tests

src/main/java/no/uib/inf101/calculator/Calculator.java

@@ -8,7 +8,17 @@ import java.util.Map;
 import no.uib.inf101.calculator.expression.BinaryExpression;
 import no.uib.inf101.calculator.expression.Expression;
 import no.uib.inf101.calculator.expression.UnaryExpression;
-import no.uib.inf101.calculator.operations.*;
+import no.uib.inf101.calculator.operations.Addition;
+import no.uib.inf101.calculator.operations.BinaryOperator;
+import no.uib.inf101.calculator.operations.Exponent;
+import no.uib.inf101.calculator.operations.Factorial;
+import no.uib.inf101.calculator.operations.Ln;
+import no.uib.inf101.calculator.operations.Log;
+import no.uib.inf101.calculator.operations.Multiplication;
+import no.uib.inf101.calculator.operations.Operator;
+import no.uib.inf101.calculator.operations.Root;
+import no.uib.inf101.calculator.operations.Subtraction;
+import no.uib.inf101.calculator.operations.UnaryOperator;
 
 /**
  * Represents a calculator that can evaluate mathematical expressions.
@@ -35,8 +45,8 @@ public class Calculator {
         addOperator(new Root());
     }
 
-    private void addOperator(String operator) {
-        operators.put(operator.getSymbol(), string);
+    private void addOperator(Operator operator) {
+        operators.put(operator.getSymbol(), operator);
     }
 
     /**

src/test/java/no/uib/inf101/calculator/CalculatorTest.java

@@ -40,6 +40,6 @@ public class CalculatorTest {
         assertEquals("Factorial: \"The product of an integer and all the integers below it\"", calc.getOperatorDescription("!"));
         assertEquals("Logarithm: \"The power to which a given number must be raised to produce 10\"", calc.getOperatorDescription("log"));
         assertEquals("Logarithm: \"The power to which e must be raised to produce a given number\"", calc.getOperatorDescription("ln"));
-        assertEquals("√", calc.getOperatorDescription("√"));
+        assertEquals("Square root: \"A number which produces a specified quantity when multiplied by itself.\"", calc.getOperatorDescription("√"));
     }
 }
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