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Posted to commits@phoenix.apache.org by ka...@apache.org on 2019/03/14 21:44:58 UTC

[phoenix] branch 4.x-HBase-1.4 updated: PHOENIX-5185 support Math PI function

This is an automated email from the ASF dual-hosted git repository.

karanmehta93 pushed a commit to branch 4.x-HBase-1.4
in repository https://gitbox.apache.org/repos/asf/phoenix.git


The following commit(s) were added to refs/heads/4.x-HBase-1.4 by this push:
     new a429f0b  PHOENIX-5185 support Math PI function
a429f0b is described below

commit a429f0b2280cfcf918b19d3edcf961ae812a8eec
Author: Xinyi Yan <He...@berkeley.edu>
AuthorDate: Thu Mar 14 14:44:54 2019 -0700

    PHOENIX-5185 support Math PI function
---
 .../phoenix/end2end/LnLogFunctionEnd2EndIT.java    | 16 ------
 .../phoenix/end2end/MathPIFunctionEnd2EndIT.java   | 61 ++++++++++++++++++++
 .../phoenix/end2end/PowerFunctionEnd2EndIT.java    | 16 ------
 .../apache/phoenix/expression/ExpressionType.java  |  1 +
 .../expression/function/MathPIFunction.java        | 65 ++++++++++++++++++++++
 .../apache/phoenix/expression/ExpFunctionTest.java | 19 +------
 .../phoenix/expression/LnLogFunctionTest.java      | 23 ++------
 .../phoenix/expression/MathPIFunctionTest.java     | 44 +++++++++++++++
 .../phoenix/expression/PowerFunctionTest.java      | 22 ++------
 .../phoenix/expression/SqrtFunctionTest.java       | 20 +------
 .../java/org/apache/phoenix/query/BaseTest.java    | 17 +++++-
 11 files changed, 199 insertions(+), 105 deletions(-)

diff --git a/phoenix-core/src/it/java/org/apache/phoenix/end2end/LnLogFunctionEnd2EndIT.java b/phoenix-core/src/it/java/org/apache/phoenix/end2end/LnLogFunctionEnd2EndIT.java
index ddbe2ad..d3d1b51 100644
--- a/phoenix-core/src/it/java/org/apache/phoenix/end2end/LnLogFunctionEnd2EndIT.java
+++ b/phoenix-core/src/it/java/org/apache/phoenix/end2end/LnLogFunctionEnd2EndIT.java
@@ -36,25 +36,9 @@ import org.junit.Test;
 public class LnLogFunctionEnd2EndIT extends ParallelStatsDisabledIT {
 
     private static final String KEY = "key";
-    private static final double ZERO = 1e-9;
     private String signedTableName;
     private String unsignedTableName;
 
-    private static boolean twoDoubleEquals(double a, double b) {
-        if (Double.isNaN(a) ^ Double.isNaN(b)) return false;
-        if (Double.isNaN(a)) return true;
-        if (Double.isInfinite(a) ^ Double.isInfinite(b)) return false;
-        if (Double.isInfinite(a)) {
-            if ((a > 0) ^ (b > 0)) return false;
-            else return true;
-        }
-        if (Math.abs(a - b) <= ZERO) {
-            return true;
-        } else {
-            return false;
-        }
-    }
-
     @Before
     public void initTable() throws Exception {
         Connection conn = null;
diff --git a/phoenix-core/src/it/java/org/apache/phoenix/end2end/MathPIFunctionEnd2EndIT.java b/phoenix-core/src/it/java/org/apache/phoenix/end2end/MathPIFunctionEnd2EndIT.java
new file mode 100644
index 0000000..9594aec
--- /dev/null
+++ b/phoenix-core/src/it/java/org/apache/phoenix/end2end/MathPIFunctionEnd2EndIT.java
@@ -0,0 +1,61 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.phoenix.end2end;
+
+import static org.junit.Assert.*;
+
+import java.sql.*;
+
+import org.apache.phoenix.exception.SQLExceptionCode;
+import org.apache.phoenix.expression.function.MathPIFunction;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * End to end tests for {@link MathPIFunction}
+ */
+public class MathPIFunctionEnd2EndIT extends ParallelStatsDisabledIT {
+
+    @Test
+    public void testGetMathPIValue() throws Exception {
+        Connection conn  = DriverManager.getConnection(getUrl());
+        ResultSet rs = conn.createStatement().executeQuery("SELECT PI()");
+        assertTrue(rs.next());
+        assertTrue(twoDoubleEquals(rs.getDouble(1), Math.PI));
+        assertFalse(rs.next());
+    }
+
+    @Test
+    public void testMathPIRoundTwoDecimal() throws Exception {
+        Connection conn  = DriverManager.getConnection(getUrl());
+        ResultSet rs = conn.createStatement().executeQuery("SELECT ROUND(PI(), 2)");
+        assertTrue(rs.next());
+        assertTrue(twoDoubleEquals(rs.getDouble(1), 3.14));
+        assertFalse(rs.next());
+    }
+
+    @Test
+    public void testMathPIFunctionWithIncorrectFormat() throws Exception {
+        Connection conn  = DriverManager.getConnection(getUrl());
+        try {
+            conn.createStatement().executeQuery("SELECT PI(1)");
+        } catch (SQLException e) {
+            assertEquals(SQLExceptionCode.FUNCTION_UNDEFINED.getErrorCode(), e.getErrorCode());
+        }
+    }
+}
diff --git a/phoenix-core/src/it/java/org/apache/phoenix/end2end/PowerFunctionEnd2EndIT.java b/phoenix-core/src/it/java/org/apache/phoenix/end2end/PowerFunctionEnd2EndIT.java
index 2d26be8..cbc6355 100644
--- a/phoenix-core/src/it/java/org/apache/phoenix/end2end/PowerFunctionEnd2EndIT.java
+++ b/phoenix-core/src/it/java/org/apache/phoenix/end2end/PowerFunctionEnd2EndIT.java
@@ -35,25 +35,9 @@ import org.junit.Test;
 public class PowerFunctionEnd2EndIT extends ParallelStatsDisabledIT {
 
     private static final String KEY = "key";
-    private static final double ZERO = 1e-9;
     private String signedTableName;
     private String unsignedTableName;
 
-    private static boolean twoDoubleEquals(double a, double b) {
-        if (Double.isNaN(a) ^ Double.isNaN(b)) return false;
-        if (Double.isNaN(a)) return true;
-        if (Double.isInfinite(a) ^ Double.isInfinite(b)) return false;
-        if (Double.isInfinite(a)) {
-            if ((a > 0) ^ (b > 0)) return false;
-            else return true;
-        }
-        if (Math.abs(a - b) <= ZERO) {
-            return true;
-        } else {
-            return false;
-        }
-    }
-
     @Before
     public void initTable() throws Exception {
         signedTableName = generateUniqueName();
diff --git a/phoenix-core/src/main/java/org/apache/phoenix/expression/ExpressionType.java b/phoenix-core/src/main/java/org/apache/phoenix/expression/ExpressionType.java
index 59c10ad..a18928c 100644
--- a/phoenix-core/src/main/java/org/apache/phoenix/expression/ExpressionType.java
+++ b/phoenix-core/src/main/java/org/apache/phoenix/expression/ExpressionType.java
@@ -187,6 +187,7 @@ public enum ExpressionType {
     CollationKeyFunction(CollationKeyFunction.class),
     ArrayRemoveFunction(ArrayRemoveFunction.class),
     TransactionProviderNameFunction(TransactionProviderNameFunction.class),
+    MathPIFunction(MathPIFunction.class),
     ;
 
     ExpressionType(Class<? extends Expression> clazz) {
diff --git a/phoenix-core/src/main/java/org/apache/phoenix/expression/function/MathPIFunction.java b/phoenix-core/src/main/java/org/apache/phoenix/expression/function/MathPIFunction.java
new file mode 100644
index 0000000..1e276ed
--- /dev/null
+++ b/phoenix-core/src/main/java/org/apache/phoenix/expression/function/MathPIFunction.java
@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.phoenix.expression.function;
+
+import java.sql.SQLException;
+import java.util.List;
+
+import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
+import org.apache.phoenix.expression.Expression;
+import org.apache.phoenix.parse.FunctionParseNode.BuiltInFunction;
+import org.apache.phoenix.schema.tuple.Tuple;
+import org.apache.phoenix.schema.types.PDataType;
+import org.apache.phoenix.schema.types.PDouble;
+
+
+/**
+ *
+ * Function used to represent PI()
+ * The function returns a {@link org.apache.phoenix.schema.types.PDouble}
+ *
+ */
+@BuiltInFunction(name = MathPIFunction.NAME, args= {}
+)
+public class MathPIFunction extends ScalarFunction {
+
+    public static final String NAME = "PI";
+
+    public MathPIFunction() {}
+
+    public MathPIFunction(List<Expression> children) throws SQLException {
+        super(children);
+    }
+
+    @Override
+    public String getName() {
+        return NAME;
+    }
+
+    @Override
+    public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
+        ptr.set(new byte[getDataType().getByteSize()]);
+        getDataType().getCodec().encodeDouble(Math.PI, ptr);
+        return true;
+    }
+
+    @Override
+    public PDataType getDataType() {
+        return PDouble.INSTANCE;
+    }
+}
diff --git a/phoenix-core/src/test/java/org/apache/phoenix/expression/ExpFunctionTest.java b/phoenix-core/src/test/java/org/apache/phoenix/expression/ExpFunctionTest.java
index b7b95c2..9521730 100644
--- a/phoenix-core/src/test/java/org/apache/phoenix/expression/ExpFunctionTest.java
+++ b/phoenix-core/src/test/java/org/apache/phoenix/expression/ExpFunctionTest.java
@@ -27,6 +27,7 @@ import java.util.Random;
 
 import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
 import org.apache.phoenix.expression.function.ExpFunction;
+import org.apache.phoenix.query.BaseTest;
 import org.apache.phoenix.schema.SortOrder;
 import org.apache.phoenix.schema.types.PDecimal;
 import org.apache.phoenix.schema.types.PDouble;
@@ -48,22 +49,6 @@ import com.google.common.collect.Lists;
  * Unit tests for {@link ExpFunction}
  */
 public class ExpFunctionTest {
-    private static final double ZERO = 1e-9;
-
-    private static boolean twoDoubleEquals(double a, double b) {
-        if (Double.isNaN(a) ^ Double.isNaN(b)) return false;
-        if (Double.isNaN(a)) return true;
-        if (Double.isInfinite(a) ^ Double.isInfinite(b)) return false;
-        if (Double.isInfinite(a)) {
-            if ((a > 0) ^ (b > 0)) return false;
-            else return true;
-        }
-        if (Math.abs(a - b) <= ZERO) {
-            return true;
-        } else {
-            return false;
-        }
-    }
 
     private static boolean testExpression(LiteralExpression literal, double expected)
             throws SQLException {
@@ -74,7 +59,7 @@ public class ExpFunctionTest {
         if (ret) {
             Double result =
                     (Double) sqrtFunction.getDataType().toObject(ptr, sqrtFunction.getSortOrder());
-            assertTrue(twoDoubleEquals(result.doubleValue(), expected));
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), expected));
         }
         return ret;
     }
diff --git a/phoenix-core/src/test/java/org/apache/phoenix/expression/LnLogFunctionTest.java b/phoenix-core/src/test/java/org/apache/phoenix/expression/LnLogFunctionTest.java
index a5e6fc7..9713bbc 100644
--- a/phoenix-core/src/test/java/org/apache/phoenix/expression/LnLogFunctionTest.java
+++ b/phoenix-core/src/test/java/org/apache/phoenix/expression/LnLogFunctionTest.java
@@ -28,6 +28,7 @@ import java.util.Random;
 import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
 import org.apache.phoenix.expression.function.LnFunction;
 import org.apache.phoenix.expression.function.LogFunction;
+import org.apache.phoenix.query.BaseTest;
 import org.apache.phoenix.schema.SortOrder;
 import org.apache.phoenix.schema.types.PDecimal;
 import org.apache.phoenix.schema.types.PDouble;
@@ -49,25 +50,9 @@ import com.google.common.collect.Lists;
  * Unit tests for {@link LnFunction} and {@link LogFunction}
  */
 public class LnLogFunctionTest {
-    private static final double ZERO = 1e-9;
     private static final Expression THREE = LiteralExpression.newConstant(3);
     private static final Expression DEFAULT_VALUE = LiteralExpression.newConstant(10.0);
 
-    private static boolean twoDoubleEquals(double a, double b) {
-        if (Double.isNaN(a) ^ Double.isNaN(b)) return false;
-        if (Double.isNaN(a)) return true;
-        if (Double.isInfinite(a) ^ Double.isInfinite(b)) return false;
-        if (Double.isInfinite(a)) {
-            if ((a > 0) ^ (b > 0)) return false;
-            else return true;
-        }
-        if (Math.abs(a - b) <= ZERO) {
-            return true;
-        } else {
-            return false;
-        }
-    }
-
     private static boolean testExpression(LiteralExpression literal, LiteralExpression literal2,
             LiteralExpression literal3, double exptForLn, double exptForLog10, double exptForLog3)
             throws SQLException {
@@ -82,7 +67,7 @@ public class LnLogFunctionTest {
         if (retLn) {
             Double result =
                     (Double) lnFunction.getDataType().toObject(ptr, lnFunction.getSortOrder());
-            assertTrue(twoDoubleEquals(result.doubleValue(), exptForLn));
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), exptForLn));
         }
 
         Expression log10Function = new LogFunction(expressionsLog10);
@@ -91,7 +76,7 @@ public class LnLogFunctionTest {
             Double result =
                     (Double) log10Function.getDataType()
                             .toObject(ptr, log10Function.getSortOrder());
-            assertTrue(twoDoubleEquals(result.doubleValue(), exptForLog10));
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), exptForLog10));
         }
         assertEquals(retLn, retLog10);
 
@@ -100,7 +85,7 @@ public class LnLogFunctionTest {
         if (retLog3) {
             Double result =
                     (Double) log3Function.getDataType().toObject(ptr, log3Function.getSortOrder());
-            assertTrue(twoDoubleEquals(result.doubleValue(), exptForLog3));
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), exptForLog3));
         }
         assertEquals(retLn, retLog3);
         return retLn;
diff --git a/phoenix-core/src/test/java/org/apache/phoenix/expression/MathPIFunctionTest.java b/phoenix-core/src/test/java/org/apache/phoenix/expression/MathPIFunctionTest.java
new file mode 100644
index 0000000..af223f2
--- /dev/null
+++ b/phoenix-core/src/test/java/org/apache/phoenix/expression/MathPIFunctionTest.java
@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.phoenix.expression;
+
+import static org.junit.Assert.assertTrue;
+
+import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
+import org.apache.phoenix.expression.function.MathPIFunction;
+import org.apache.phoenix.query.BaseTest;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link MathPIFunction}
+ */
+public class MathPIFunctionTest {
+
+    @Test
+    public void testMathPIFunction() {
+        Expression mathPIFunction = new MathPIFunction();
+        ImmutableBytesWritable ptr = new ImmutableBytesWritable();
+        boolean res = mathPIFunction.evaluate(null, ptr);
+        if (res) {
+            Double result = (Double) mathPIFunction.getDataType().toObject(ptr);
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), Math.PI));
+        }
+        assertTrue(res);
+    }
+}
diff --git a/phoenix-core/src/test/java/org/apache/phoenix/expression/PowerFunctionTest.java b/phoenix-core/src/test/java/org/apache/phoenix/expression/PowerFunctionTest.java
index 9710e52..9349445 100644
--- a/phoenix-core/src/test/java/org/apache/phoenix/expression/PowerFunctionTest.java
+++ b/phoenix-core/src/test/java/org/apache/phoenix/expression/PowerFunctionTest.java
@@ -27,6 +27,7 @@ import java.util.Random;
 
 import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
 import org.apache.phoenix.expression.function.PowerFunction;
+import org.apache.phoenix.query.BaseTest;
 import org.apache.phoenix.schema.SortOrder;
 import org.apache.phoenix.schema.types.PDecimal;
 import org.apache.phoenix.schema.types.PDouble;
@@ -48,25 +49,10 @@ import com.google.common.collect.Lists;
  * Unit tests for {@link PowerFunction}
  */
 public class PowerFunctionTest {
-    private static final double ZERO = 1e-9;
     private static final Expression ONE_POINT_FIVE = LiteralExpression.newConstant(1.5);
     private static final Expression TWO = LiteralExpression.newConstant(2);
     private static final Expression THREE = LiteralExpression.newConstant(3);
 
-    private static boolean twoDoubleEquals(double a, double b) {
-        if (Double.isNaN(a) ^ Double.isNaN(b)) return false;
-        if (Double.isNaN(a)) return true;
-        if (Double.isInfinite(a) ^ Double.isInfinite(b)) return false;
-        if (Double.isInfinite(a)) {
-            if ((a > 0) ^ (b > 0)) return false;
-            else return true;
-        }
-        if (Math.abs(a - b) <= ZERO) {
-            return true;
-        } else {
-            return false;
-        }
-    }
 
     private static boolean testExpression(LiteralExpression literal, LiteralExpression literal2,
             LiteralExpression literal3, double exptFor15, double exptFor2, double exptFor3)
@@ -83,7 +69,7 @@ public class PowerFunctionTest {
             Double result =
                     (Double) powerFunction15.getDataType().toObject(ptr,
                         powerFunction15.getSortOrder());
-            assertTrue(twoDoubleEquals(result.doubleValue(), exptFor15));
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), exptFor15));
         }
 
         Expression powerFunction2 = new PowerFunction(expressions2);
@@ -92,7 +78,7 @@ public class PowerFunctionTest {
             Double result =
                     (Double) powerFunction2.getDataType().toObject(ptr,
                         powerFunction2.getSortOrder());
-            assertTrue(twoDoubleEquals(result.doubleValue(), exptFor2));
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), exptFor2));
         }
         assertEquals(ret15, ret2);
 
@@ -102,7 +88,7 @@ public class PowerFunctionTest {
             Double result =
                     (Double) powerFunction3.getDataType().toObject(ptr,
                         powerFunction3.getSortOrder());
-            assertTrue(twoDoubleEquals(result.doubleValue(), exptFor3));
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), exptFor3));
         }
         assertEquals(ret15, ret3);
         return ret15;
diff --git a/phoenix-core/src/test/java/org/apache/phoenix/expression/SqrtFunctionTest.java b/phoenix-core/src/test/java/org/apache/phoenix/expression/SqrtFunctionTest.java
index 6b19ad8..ee065ab 100644
--- a/phoenix-core/src/test/java/org/apache/phoenix/expression/SqrtFunctionTest.java
+++ b/phoenix-core/src/test/java/org/apache/phoenix/expression/SqrtFunctionTest.java
@@ -27,6 +27,7 @@ import java.util.Random;
 
 import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
 import org.apache.phoenix.expression.function.SqrtFunction;
+import org.apache.phoenix.query.BaseTest;
 import org.apache.phoenix.schema.SortOrder;
 import org.apache.phoenix.schema.types.PDecimal;
 import org.apache.phoenix.schema.types.PDouble;
@@ -48,23 +49,6 @@ import com.google.common.collect.Lists;
  * Unit tests for {@link SqrtFunction}
  */
 public class SqrtFunctionTest {
-    private static final double ZERO = 1e-9;
-
-    private static boolean twoDoubleEquals(double a, double b) {
-        if (Double.isNaN(a) ^ Double.isNaN(b)) return false;
-        if (Double.isNaN(a)) return true;
-        if (Double.isInfinite(a) ^ Double.isInfinite(b)) return false;
-        if (Double.isInfinite(a)) {
-            if ((a > 0) ^ (b > 0)) return false;
-            else return true;
-        }
-        if (Math.abs(a - b) <= ZERO) {
-            return true;
-        } else {
-            return false;
-        }
-    }
-
     private static boolean testExpression(LiteralExpression literal, double expected)
             throws SQLException {
         List<Expression> expressions = Lists.newArrayList((Expression) literal);
@@ -74,7 +58,7 @@ public class SqrtFunctionTest {
         if (ret) {
             Double result =
                     (Double) sqrtFunction.getDataType().toObject(ptr, sqrtFunction.getSortOrder());
-            assertTrue(twoDoubleEquals(result.doubleValue(), expected));
+            assertTrue(BaseTest.twoDoubleEquals(result.doubleValue(), expected));
         }
         return ret;
     }
diff --git a/phoenix-core/src/test/java/org/apache/phoenix/query/BaseTest.java b/phoenix-core/src/test/java/org/apache/phoenix/query/BaseTest.java
index 49278a8..305249b 100644
--- a/phoenix-core/src/test/java/org/apache/phoenix/query/BaseTest.java
+++ b/phoenix-core/src/test/java/org/apache/phoenix/query/BaseTest.java
@@ -179,7 +179,7 @@ import com.google.common.util.concurrent.ThreadFactoryBuilder;
 
 public abstract class BaseTest {
     public static final String DRIVER_CLASS_NAME_ATTRIB = "phoenix.driver.class.name";
-    
+    private static final double ZERO = 1e-9;
     private static final Map<String,String> tableDDLMap;
     private static final Logger logger = LoggerFactory.getLogger(BaseTest.class);
     @ClassRule
@@ -685,6 +685,21 @@ public abstract class BaseTest {
         return timestamp;
     }
 
+    public static boolean twoDoubleEquals(double a, double b) {
+        if (Double.isNaN(a) ^ Double.isNaN(b)) return false;
+        if (Double.isNaN(a)) return true;
+        if (Double.isInfinite(a) ^ Double.isInfinite(b)) return false;
+        if (Double.isInfinite(a)) {
+            if ((a > 0) ^ (b > 0)) return false;
+            else return true;
+        }
+        if (Math.abs(a - b) <= ZERO) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
     protected static void ensureTableCreated(String url, String tableName) throws SQLException {
         ensureTableCreated(url, tableName, tableName, null, null, null);
     }