[SPARK-10547] [TEST] Streamline / improve style of Java API tests

Fix a few Java API test style issues: unused generic types, exceptions, wrong assert argument order

Author: Sean Owen <sowen@cloudera.com>

Closes #8706 from srowen/SPARK-10547.

5 files changed, 54 insertions, 48 deletions

diff --git a/sql/core/src/test/java/test/org/apache/spark/sql/JavaApplySchemaSuite.java b/sql/core/src/test/java/test/org/apache/spark/sql/JavaApplySchemaSuite.java
index bf693c7c39..7b50aad4ad 100644
--- a/sql/core/src/test/java/test/org/apache/spark/sql/JavaApplySchemaSuite.java
+++ b/sql/core/src/test/java/test/org/apache/spark/sql/JavaApplySchemaSuite.java
@@ -18,6 +18,7 @@
 package test.org.apache.spark.sql;
 
 import java.io.Serializable;
+import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -83,7 +84,7 @@ public class JavaApplySchemaSuite implements Serializable {
 
   @Test
   public void applySchema() {
-    List<Person> personList = new ArrayList<Person>(2);
+    List<Person> personList = new ArrayList<>(2);
     Person person1 = new Person();
     person1.setName("Michael");
     person1.setAge(29);
@@ -95,12 +96,13 @@ public class JavaApplySchemaSuite implements Serializable {
 
     JavaRDD<Row> rowRDD = javaCtx.parallelize(personList).map(
       new Function<Person, Row>() {
+        @Override
         public Row call(Person person) throws Exception {
           return RowFactory.create(person.getName(), person.getAge());
         }
       });
 
-    List<StructField> fields = new ArrayList<StructField>(2);
+    List<StructField> fields = new ArrayList<>(2);
     fields.add(DataTypes.createStructField("name", DataTypes.StringType, false));
     fields.add(DataTypes.createStructField("age", DataTypes.IntegerType, false));
     StructType schema = DataTypes.createStructType(fields);
@@ -118,7 +120,7 @@ public class JavaApplySchemaSuite implements Serializable {
 
   @Test
   public void dataFrameRDDOperations() {
-    List<Person> personList = new ArrayList<Person>(2);
+    List<Person> personList = new ArrayList<>(2);
     Person person1 = new Person();
     person1.setName("Michael");
     person1.setAge(29);
@@ -129,27 +131,28 @@ public class JavaApplySchemaSuite implements Serializable {
     personList.add(person2);
 
     JavaRDD<Row> rowRDD = javaCtx.parallelize(personList).map(
-            new Function<Person, Row>() {
-              public Row call(Person person) throws Exception {
-                return RowFactory.create(person.getName(), person.getAge());
-              }
-            });
-
-    List<StructField> fields = new ArrayList<StructField>(2);
-    fields.add(DataTypes.createStructField("name", DataTypes.StringType, false));
+        new Function<Person, Row>() {
+          @Override
+          public Row call(Person person) {
+            return RowFactory.create(person.getName(), person.getAge());
+          }
+        });
+
+    List<StructField> fields = new ArrayList<>(2);
+    fields.add(DataTypes.createStructField("", DataTypes.StringType, false));
     fields.add(DataTypes.createStructField("age", DataTypes.IntegerType, false));
     StructType schema = DataTypes.createStructType(fields);
 
     DataFrame df = sqlContext.applySchema(rowRDD, schema);
     df.registerTempTable("people");
     List<String> actual = sqlContext.sql("SELECT * FROM people").toJavaRDD().map(new Function<Row, String>() {
-
+      @Override
       public String call(Row row) {
-        return row.getString(0) + "_" + row.get(1).toString();
+        return row.getString(0) + "_" + row.get(1);
       }
     }).collect();
 
-    List<String> expected = new ArrayList<String>(2);
+    List<String> expected = new ArrayList<>(2);
     expected.add("Michael_29");
     expected.add("Yin_28");
 
@@ -165,7 +168,7 @@ public class JavaApplySchemaSuite implements Serializable {
       "{\"string\":\"this is another simple string.\", \"integer\":11, \"long\":21474836469, " +
         "\"bigInteger\":92233720368547758069, \"double\":1.7976931348623157E305, " +
         "\"boolean\":false, \"null\":null}"));
-    List<StructField> fields = new ArrayList<StructField>(7);
+    List<StructField> fields = new ArrayList<>(7);
     fields.add(DataTypes.createStructField("bigInteger", DataTypes.createDecimalType(20, 0),
       true));
     fields.add(DataTypes.createStructField("boolean", DataTypes.BooleanType, true));
@@ -175,10 +178,10 @@ public class JavaApplySchemaSuite implements Serializable {
     fields.add(DataTypes.createStructField("null", DataTypes.StringType, true));
     fields.add(DataTypes.createStructField("string", DataTypes.StringType, true));
     StructType expectedSchema = DataTypes.createStructType(fields);
-    List<Row> expectedResult = new ArrayList<Row>(2);
+    List<Row> expectedResult = new ArrayList<>(2);
     expectedResult.add(
       RowFactory.create(
-        new java.math.BigDecimal("92233720368547758070"),
+        new BigDecimal("92233720368547758070"),
         true,
         1.7976931348623157E308,
         10,
@@ -187,7 +190,7 @@ public class JavaApplySchemaSuite implements Serializable {
         "this is a simple string."));
     expectedResult.add(
       RowFactory.create(
-        new java.math.BigDecimal("92233720368547758069"),
+        new BigDecimal("92233720368547758069"),
         false,
         1.7976931348623157E305,
         11,
diff --git a/sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java b/sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java
index 4867cebf53..d981ce947f 100644
--- a/sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java
+++ b/sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java
@@ -61,7 +61,7 @@ public class JavaDataFrameSuite {
   @Test
   public void testExecution() {
     DataFrame df = context.table("testData").filter("key = 1");
-    Assert.assertEquals(df.select("key").collect()[0].get(0), 1);
+    Assert.assertEquals(1, df.select("key").collect()[0].get(0));
   }
 
   /**
@@ -119,7 +119,7 @@ public class JavaDataFrameSuite {
 
   public static class Bean implements Serializable {
     private double a = 0.0;
-    private Integer[] b = new Integer[]{0, 1};
+    private Integer[] b = { 0, 1 };
     private Map<String, int[]> c = ImmutableMap.of("hello", new int[] { 1, 2 });
     private List<String> d = Arrays.asList("floppy", "disk");
 
@@ -161,7 +161,7 @@ public class JavaDataFrameSuite {
       schema.apply("d"));
     Row first = df.select("a", "b", "c", "d").first();
     Assert.assertEquals(bean.getA(), first.getDouble(0), 0.0);
-    // Now Java lists and maps are converetd to Scala Seq's and Map's. Once we get a Seq below,
+    // Now Java lists and maps are converted to Scala Seq's and Map's. Once we get a Seq below,
     // verify that it has the expected length, and contains expected elements.
     Seq<Integer> result = first.getAs(1);
     Assert.assertEquals(bean.getB().length, result.length());
@@ -180,7 +180,8 @@ public class JavaDataFrameSuite {
     }
   }
 
-  private static Comparator<Row> CrosstabRowComparator = new Comparator<Row>() {
+  private static final Comparator<Row> crosstabRowComparator = new Comparator<Row>() {
+    @Override
     public int compare(Row row1, Row row2) {
       String item1 = row1.getString(0);
       String item2 = row2.getString(0);
@@ -193,16 +194,16 @@ public class JavaDataFrameSuite {
     DataFrame df = context.table("testData2");
     DataFrame crosstab = df.stat().crosstab("a", "b");
     String[] columnNames = crosstab.schema().fieldNames();
-    Assert.assertEquals(columnNames[0], "a_b");
-    Assert.assertEquals(columnNames[1], "1");
-    Assert.assertEquals(columnNames[2], "2");
+    Assert.assertEquals("a_b", columnNames[0]);
+    Assert.assertEquals("1", columnNames[1]);
+    Assert.assertEquals("2", columnNames[2]);
     Row[] rows = crosstab.collect();
-    Arrays.sort(rows, CrosstabRowComparator);
+    Arrays.sort(rows, crosstabRowComparator);
     Integer count = 1;
     for (Row row : rows) {
       Assert.assertEquals(row.get(0).toString(), count.toString());
-      Assert.assertEquals(row.getLong(1), 1L);
-      Assert.assertEquals(row.getLong(2), 1L);
+      Assert.assertEquals(1L, row.getLong(1));
+      Assert.assertEquals(1L, row.getLong(2));
       count++;
     }
   }
@@ -210,7 +211,7 @@ public class JavaDataFrameSuite {
   @Test
   public void testFrequentItems() {
     DataFrame df = context.table("testData2");
-    String[] cols = new String[]{"a"};
+    String[] cols = {"a"};
     DataFrame results = df.stat().freqItems(cols, 0.2);
     Assert.assertTrue(results.collect()[0].getSeq(0).contains(1));
   }
@@ -219,14 +220,14 @@ public class JavaDataFrameSuite {
   public void testCorrelation() {
     DataFrame df = context.table("testData2");
     Double pearsonCorr = df.stat().corr("a", "b", "pearson");
-    Assert.assertTrue(Math.abs(pearsonCorr) < 1e-6);
+    Assert.assertTrue(Math.abs(pearsonCorr) < 1.0e-6);
   }
 
   @Test
   public void testCovariance() {
     DataFrame df = context.table("testData2");
     Double result = df.stat().cov("a", "b");
-    Assert.assertTrue(Math.abs(result) < 1e-6);
+    Assert.assertTrue(Math.abs(result) < 1.0e-6);
   }
 
   @Test
@@ -234,7 +235,7 @@ public class JavaDataFrameSuite {
     DataFrame df = context.range(0, 100, 1, 2).select(col("id").mod(3).as("key"));
     DataFrame sampled = df.stat().<Integer>sampleBy("key", ImmutableMap.of(0, 0.1, 1, 0.2), 0L);
     Row[] actual = sampled.groupBy("key").count().orderBy("key").collect();
-    Row[] expected = new Row[] {RowFactory.create(0, 5), RowFactory.create(1, 8)};
+    Row[] expected = {RowFactory.create(0, 5), RowFactory.create(1, 8)};
     Assert.assertArrayEquals(expected, actual);
   }
 }
diff --git a/sql/core/src/test/java/test/org/apache/spark/sql/JavaRowSuite.java b/sql/core/src/test/java/test/org/apache/spark/sql/JavaRowSuite.java
index 4ce1d1dddb..3ab4db2a03 100644
--- a/sql/core/src/test/java/test/org/apache/spark/sql/JavaRowSuite.java
+++ b/sql/core/src/test/java/test/org/apache/spark/sql/JavaRowSuite.java
@@ -18,6 +18,7 @@
 package test.org.apache.spark.sql;
 
 import java.math.BigDecimal;
+import java.nio.charset.StandardCharsets;
 import java.sql.Date;
 import java.sql.Timestamp;
 import java.util.Arrays;
@@ -52,12 +53,12 @@ public class JavaRowSuite {
     shortValue = (short)32767;
     intValue = 2147483647;
     longValue = 9223372036854775807L;
-    floatValue = (float)3.4028235E38;
+    floatValue = 3.4028235E38f;
     doubleValue = 1.7976931348623157E308;
     decimalValue = new BigDecimal("1.7976931348623157E328");
     booleanValue = true;
     stringValue = "this is a string";
-    binaryValue = stringValue.getBytes();
+    binaryValue = stringValue.getBytes(StandardCharsets.UTF_8);
     dateValue = Date.valueOf("2014-06-30");
     timestampValue = Timestamp.valueOf("2014-06-30 09:20:00.0");
   }
@@ -123,8 +124,8 @@ public class JavaRowSuite {
     Assert.assertEquals(binaryValue, simpleRow.get(16));
     Assert.assertEquals(dateValue, simpleRow.get(17));
     Assert.assertEquals(timestampValue, simpleRow.get(18));
-    Assert.assertEquals(true, simpleRow.isNullAt(19));
-    Assert.assertEquals(null, simpleRow.get(19));
+    Assert.assertTrue(simpleRow.isNullAt(19));
+    Assert.assertNull(simpleRow.get(19));
   }
 
   @Test
@@ -134,7 +135,7 @@ public class JavaRowSuite {
       stringValue + " (1)", stringValue + " (2)", stringValue + "(3)");
 
     // Simple map
-    Map<String, Long> simpleMap = new HashMap<String, Long>();
+    Map<String, Long> simpleMap = new HashMap<>();
     simpleMap.put(stringValue + " (1)", longValue);
     simpleMap.put(stringValue + " (2)", longValue - 1);
     simpleMap.put(stringValue + " (3)", longValue - 2);
@@ -149,7 +150,7 @@ public class JavaRowSuite {
     List<Row> arrayOfRows = Arrays.asList(simpleStruct);
 
     // Complex map
-    Map<List<Row>, Row> complexMap = new HashMap<List<Row>, Row>();
+    Map<List<Row>, Row> complexMap = new HashMap<>();
     complexMap.put(arrayOfRows, simpleStruct);
 
     // Complex struct
@@ -167,7 +168,7 @@ public class JavaRowSuite {
     Assert.assertEquals(arrayOfMaps, complexStruct.get(3));
     Assert.assertEquals(arrayOfRows, complexStruct.get(4));
     Assert.assertEquals(complexMap, complexStruct.get(5));
-    Assert.assertEquals(null, complexStruct.get(6));
+    Assert.assertNull(complexStruct.get(6));
 
     // A very complex row
     Row complexRow = RowFactory.create(arrayOfMaps, arrayOfRows, complexMap, complexStruct);
diff --git a/sql/core/src/test/java/test/org/apache/spark/sql/JavaUDFSuite.java b/sql/core/src/test/java/test/org/apache/spark/sql/JavaUDFSuite.java
index bb02b58cca..4a78dca7fe 100644
--- a/sql/core/src/test/java/test/org/apache/spark/sql/JavaUDFSuite.java
+++ b/sql/core/src/test/java/test/org/apache/spark/sql/JavaUDFSuite.java
@@ -20,6 +20,7 @@ package test.org.apache.spark.sql;
 import java.io.Serializable;
 
 import org.junit.After;
+import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -61,13 +62,13 @@ public class JavaUDFSuite implements Serializable {
 
     sqlContext.udf().register("stringLengthTest", new UDF1<String, Integer>() {
       @Override
-      public Integer call(String str) throws Exception {
+      public Integer call(String str) {
         return str.length();
       }
     }, DataTypes.IntegerType);
 
     Row result = sqlContext.sql("SELECT stringLengthTest('test')").head();
-    assert(result.getInt(0) == 4);
+    Assert.assertEquals(4, result.getInt(0));
   }
 
   @SuppressWarnings("unchecked")
@@ -81,12 +82,12 @@ public class JavaUDFSuite implements Serializable {
 
     sqlContext.udf().register("stringLengthTest", new UDF2<String, String, Integer>() {
       @Override
-      public Integer call(String str1, String str2) throws Exception {
+      public Integer call(String str1, String str2) {
         return str1.length() + str2.length();
       }
     }, DataTypes.IntegerType);
 
     Row result = sqlContext.sql("SELECT stringLengthTest('test', 'test2')").head();
-    assert(result.getInt(0) == 9);
+    Assert.assertEquals(9, result.getInt(0));
   }
 }
diff --git a/sql/core/src/test/java/test/org/apache/spark/sql/sources/JavaSaveLoadSuite.java b/sql/core/src/test/java/test/org/apache/spark/sql/sources/JavaSaveLoadSuite.java
index 6f9e7f68dc..9e241f2098 100644
--- a/sql/core/src/test/java/test/org/apache/spark/sql/sources/JavaSaveLoadSuite.java
+++ b/sql/core/src/test/java/test/org/apache/spark/sql/sources/JavaSaveLoadSuite.java
@@ -44,7 +44,7 @@ public class JavaSaveLoadSuite {
   File path;
   DataFrame df;
 
-  private void checkAnswer(DataFrame actual, List<Row> expected) {
+  private static void checkAnswer(DataFrame actual, List<Row> expected) {
     String errorMessage = QueryTest$.MODULE$.checkAnswer(actual, expected);
     if (errorMessage != null) {
       Assert.fail(errorMessage);
@@ -64,7 +64,7 @@ public class JavaSaveLoadSuite {
       path.delete();
     }
 
-    List<String> jsonObjects = new ArrayList<String>(10);
+    List<String> jsonObjects = new ArrayList<>(10);
     for (int i = 0; i < 10; i++) {
       jsonObjects.add("{\"a\":" + i + ", \"b\":\"str" + i + "\"}");
     }
@@ -82,7 +82,7 @@ public class JavaSaveLoadSuite {
 
   @Test
   public void saveAndLoad() {
-    Map<String, String> options = new HashMap<String, String>();
+    Map<String, String> options = new HashMap<>();
     options.put("path", path.toString());
     df.write().mode(SaveMode.ErrorIfExists).format("json").options(options).save();
     DataFrame loadedDF = sqlContext.read().format("json").options(options).load();
@@ -91,11 +91,11 @@ public class JavaSaveLoadSuite {
 
   @Test
   public void saveAndLoadWithSchema() {
-    Map<String, String> options = new HashMap<String, String>();
+    Map<String, String> options = new HashMap<>();
     options.put("path", path.toString());
     df.write().format("json").mode(SaveMode.ErrorIfExists).options(options).save();
 
-    List<StructField> fields = new ArrayList<StructField>();
+    List<StructField> fields = new ArrayList<>();
     fields.add(DataTypes.createStructField("b", DataTypes.StringType, true));
     StructType schema = DataTypes.createStructType(fields);
     DataFrame loadedDF = sqlContext.read().format("json").schema(schema).options(options).load();