plugins/IntentionPowerPak/src/com/siyeh/ipp/junit/CreateAssertIntention.java

/*
 * Copyright 2003-2014 Dave Griffith, Bas Leijdekkers
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.siyeh.ipp.junit;

import com.intellij.psi.*;
import com.intellij.psi.tree.IElementType;
import com.siyeh.ig.PsiReplacementUtil;
import com.siyeh.ig.psiutils.ExpressionUtils;
import com.siyeh.ig.psiutils.ImportUtils;
import com.siyeh.ipp.base.Intention;
import com.siyeh.ipp.base.PsiElementPredicate;
import com.siyeh.ipp.psiutils.BoolUtils;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;

public class CreateAssertIntention extends Intention {

  @NotNull
  public PsiElementPredicate getElementPredicate() {
    return new CreateAssertPredicate();
  }

  public void processIntention(PsiElement element) {
    final PsiExpressionStatement statement = (PsiExpressionStatement)element;
    final PsiExpression expression = statement.getExpression();
    final String newStatement;
    if (BoolUtils.isNegation(expression)) {
      newStatement = buildNewStatement("assertFalse", element, BoolUtils.getNegatedExpressionText(expression));
    }
    else if (isNullComparison(expression)) {
      final PsiBinaryExpression binaryExpression =
        (PsiBinaryExpression)expression;
      final PsiExpression lhs = binaryExpression.getLOperand();
      final PsiExpression rhs = binaryExpression.getROperand();
      final PsiExpression comparedExpression;
      if (ExpressionUtils.isNullLiteral(lhs)) {
        comparedExpression = rhs;
      }
      else {
        comparedExpression = lhs;
      }
      assert comparedExpression != null;
      if (JavaTokenType.EQEQ.equals(binaryExpression.getOperationTokenType())) {
        newStatement = buildNewStatement("assertNull", element, comparedExpression.getText());
      }
      else {
        newStatement = buildNewStatement("assertNotNull", element, comparedExpression.getText());
      }
    }
    else if (isEqualityComparison(expression)) {
      final PsiBinaryExpression binaryExpression =
        (PsiBinaryExpression)expression;
      final PsiExpression lhs = binaryExpression.getLOperand();
      final PsiExpression rhs = binaryExpression.getROperand();
      final PsiExpression comparedExpression;
      final PsiExpression comparingExpression;
      if (rhs instanceof PsiLiteralExpression) {
        comparedExpression = rhs;
        comparingExpression = lhs;
      }
      else {
        comparedExpression = lhs;
        comparingExpression = rhs;
      }
      assert comparingExpression != null;
      final PsiType type = lhs.getType();
      if (PsiType.DOUBLE.equals(type) || PsiType.FLOAT.equals(type)) {
        newStatement = buildNewStatement("assertEquals",
                                          element, comparedExpression.getText(), comparingExpression.getText(), "0.0");
      }
      else if (type instanceof PsiPrimitiveType) {
        newStatement = buildNewStatement("assertEquals", element, comparedExpression.getText(), comparingExpression.getText());
      }
      else {
        newStatement = buildNewStatement("assertSame", element, comparedExpression.getText(), comparingExpression.getText());
      }
    }
    else if (isEqualsExpression(expression)) {
      final PsiMethodCallExpression call =
        (PsiMethodCallExpression)expression;
      final PsiReferenceExpression methodExpression =
        call.getMethodExpression();
      final PsiExpression comparedExpression =
        methodExpression.getQualifierExpression();
      assert comparedExpression != null;
      final PsiExpressionList argList = call.getArgumentList();
      final PsiExpression comparingExpression = argList.getExpressions()[0];
      if (comparingExpression instanceof PsiLiteralExpression) {
        newStatement = buildNewStatement("assertEquals", element, comparingExpression.getText(), comparedExpression.getText());
      }
      else {
        newStatement = buildNewStatement("assertEquals", element, comparedExpression.getText(), comparingExpression.getText());
      }
    }
    else {
      newStatement = buildNewStatement("assertTrue", element, expression.getText());
    }
    PsiReplacementUtil.replaceStatementAndShortenClassNames(statement, newStatement);
  }

  @NonNls
  private static String buildNewStatement(@NonNls String memberName, PsiElement context, String... argumentTexts) {
    final PsiElementFactory factory = JavaPsiFacade.getElementFactory(context.getProject());
    final StringBuilder builder = new StringBuilder(memberName).append('(');
    boolean comma = false;
    for (String argumentText : argumentTexts) {
      if (comma) {
        builder.append(',');
      }
      else {
        comma = true;
      }
      builder.append(argumentText);
    }
    builder.append(')');
    final String text = builder.toString();

    final PsiMethodCallExpression methodCallExpression = (PsiMethodCallExpression)factory.createExpressionFromText(text, context);
    final PsiMethod method = methodCallExpression.resolveMethod();
    if (method != null || hasStaticImports(context) && ImportUtils.addStaticImport("org.junit.Assert", memberName, context)) {
      return text + ';';
    }
    else {
      return "org.junit.Assert." + text + ';';
    }
  }

  private static boolean hasStaticImports(PsiElement element) {
    final PsiFile file = element.getContainingFile();
    if (!(file instanceof PsiJavaFile)) {
      return false;
    }
    final PsiJavaFile javaFile = (PsiJavaFile)file;
    final PsiImportList importList = javaFile.getImportList();
    return importList != null && importList.getImportStaticStatements().length > 0;
  }

  private static boolean isEqualsExpression(PsiExpression expression) {
    if (!(expression instanceof PsiMethodCallExpression)) {
      return false;
    }
    final PsiMethodCallExpression call =
      (PsiMethodCallExpression)expression;
    final PsiReferenceExpression methodExpression =
      call.getMethodExpression();
    @NonNls final String methodName = methodExpression.getReferenceName();
    if (!"equals".equals(methodName)) {
      return false;
    }
    final PsiExpression qualifier =
      methodExpression.getQualifierExpression();
    if (qualifier == null) {
      return false;
    }
    final PsiExpressionList argList = call.getArgumentList();
    final PsiExpression[] expressions = argList.getExpressions();
    return expressions.length == 1 && expressions[0] != null;
  }

  private static boolean isEqualityComparison(PsiExpression expression) {
    if (!(expression instanceof PsiBinaryExpression)) {
      return false;
    }
    final PsiBinaryExpression binaryExpression =
      (PsiBinaryExpression)expression;
    final IElementType tokenType = binaryExpression.getOperationTokenType();
    return JavaTokenType.EQEQ.equals(tokenType);
  }

  private static boolean isNullComparison(PsiExpression expression) {
    if (!(expression instanceof PsiBinaryExpression)) {
      return false;
    }
    final PsiBinaryExpression binaryExpression = (PsiBinaryExpression)expression;
    final IElementType tokenType = binaryExpression.getOperationTokenType();
    if (!JavaTokenType.EQEQ.equals(tokenType) && !JavaTokenType.NE.equals(tokenType)) {
      return false;
    }
    final PsiExpression lhs = binaryExpression.getLOperand();
    if (ExpressionUtils.isNullLiteral(lhs)) {
      return true;
    }
    final PsiExpression rhs = binaryExpression.getROperand();
    return ExpressionUtils.isNullLiteral(rhs);
  }
}