diff --git a/main/tests/server/src/com/google/refine/RefineTest.java b/main/tests/server/src/com/google/refine/RefineTest.java
index af4f27bc6..ccecc9839 100644
--- a/main/tests/server/src/com/google/refine/RefineTest.java
+++ b/main/tests/server/src/com/google/refine/RefineTest.java
@@ -95,7 +95,8 @@ public class RefineTest extends PowerMockTestCase {
             FileUtils.writeStringToFile(jsonPath, "{\"projectIDs\":[]\n" + 
                     ",\"preferences\":{\"entries\":{\"scripting.starred-expressions\":" +
                     "{\"class\":\"com.google.refine.preference.TopList\",\"top\":2147483647," +
-                    "\"list\":[]},\"scripting.expressions\":{\"class\":\"com.google.refine.preference.TopList\",\"top\":100,\"list\":[]}}}}");
+                    "\"list\":[]},\"scripting.expressions\":{\"class\":\"com.google.refine.preference.TopList\",\"top\":100,\"list\":[]}}}}",
+                    "UTF-8"); // JSON is always UTF-8
             FileProjectManager.initialize(workspaceDir);
             
 
diff --git a/main/tests/server/src/com/google/refine/expr/functions/ToNumberTests.java b/main/tests/server/src/com/google/refine/expr/functions/ToNumberTests.java
index e94ba1dd9..8274392bf 100644
--- a/main/tests/server/src/com/google/refine/expr/functions/ToNumberTests.java
+++ b/main/tests/server/src/com/google/refine/expr/functions/ToNumberTests.java
@@ -26,16 +26,35 @@
  ******************************************************************************/
 package com.google.refine.expr.functions;
 
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+
+import java.util.Properties;
+
 import org.testng.annotations.Test;
 
-import com.google.refine.expr.functions.ToNumber;
+import com.google.refine.expr.EvalError;
+import com.google.refine.grel.Function;
 import com.google.refine.util.TestUtils;
 
 public class ToNumberTests {
+
+    private static final Double EPSILON = 0.000001;
+    static Properties bindings = new Properties();
+
     @Test
     public void serializeToNumber() {
         String json = "{\"description\":\"Returns o converted to a number\",\"params\":\"o\",\"returns\":\"number\"}";
         TestUtils.isSerializedTo(new ToNumber(), json);
     }
+
+    @Test
+    public void testConversions() {
+        Function f = new ToNumber();
+        assertEquals(f.call(bindings, new Object[] {Long.valueOf(11)}), Long.valueOf(11));
+        assertEquals(f.call(bindings, new Object[] {"12"}), Long.valueOf(12));
+        assertTrue((Double)f.call(bindings, new Object[] {"12345.6789"}) - Double.valueOf(12345.6789) < EPSILON);
+        assertTrue(f.call(bindings, new Object[] {"abc"}) instanceof EvalError);
+        }
 }
 
diff --git a/main/tests/server/src/com/google/refine/grel/FunctionTests.java b/main/tests/server/src/com/google/refine/grel/FunctionTests.java
index dfb987d5a..5e671e5c2 100644
--- a/main/tests/server/src/com/google/refine/grel/FunctionTests.java
+++ b/main/tests/server/src/com/google/refine/grel/FunctionTests.java
@@ -33,8 +33,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
 package com.google.refine.grel;
 
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertNull;
+import static org.testng.Assert.assertTrue;
+
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Map.Entry;
 import java.util.Properties;
+import java.util.Set;
 
 import org.slf4j.LoggerFactory;
 import org.testng.Assert;
@@ -118,4 +126,54 @@ public class FunctionTests extends RefineTest {
         Assert.assertEquals(invoke("facetCount", new Integer(1), "value", "Column A"),Integer.valueOf(5));
         Assert.assertEquals(invoke("facetCount", new Integer(2), "value+1", "Column A"),Integer.valueOf(5));
     }
+
+    @Test
+    void testZeroArgs() {
+        Set<String> valid0args = new HashSet<>(Arrays.asList("now")); // valid 0-arg returns datetype
+        // Not sure which, if any, of these are intended, but fixing them may break existing scripts
+        Set<String> returnsNull = new HashSet<>(Arrays.asList("chomp", "contains", "escape", "unescape", "exp",
+                "fingerprint", "get", "jsonize", "parseJson", "partition", "pow", "rpartition",
+                "slice", "substring", // synonyms for Slice
+                "unicode", "unicodeType"
+                ));
+        Set<String> returnsFalse = new HashSet<>(Arrays.asList("hasField"));
+
+        for (Entry<String, Function> entry : ControlFunctionRegistry.getFunctionMapping()) {
+            Function func = entry.getValue();
+            Object result = func.call(bindings, new Object[0]);
+            if (returnsNull.contains(ControlFunctionRegistry.getFunctionName(func))) {
+                assertNull(result, ControlFunctionRegistry.getFunctionName(func) + " didn't return null on 0 args");
+            } else if (returnsFalse.contains(ControlFunctionRegistry.getFunctionName(func))) {
+                assertEquals(result, Boolean.FALSE, ControlFunctionRegistry.getFunctionName(func) + " didn't return false on 0 args");
+            } else if (!valid0args.contains(ControlFunctionRegistry.getFunctionName(func))) {
+                assertTrue(result instanceof EvalError, ControlFunctionRegistry.getFunctionName(func) + " didn't error on 0 args");
+            }
+        }
+    }
+
+    @Test
+    void testTooManyArgs() {
+        // Not sure which, if any, of these are intended, but fixing them may break existing scripts
+        Set<String> returnsNull = new HashSet<>(Arrays.asList("chomp", "contains", "coalesce", "escape", "unescape",
+                "exp", "fingerprint", "get", "now", "parseJson", "partition", "pow", "rpartition",
+                "slice", "substring", // synonyms for Slice
+                "unicode", "unicodeType"
+                ));
+        Set<String> returnsFalse = new HashSet<>(Arrays.asList("hasField"));
+        Set<String> exempt = new HashSet<>(Arrays.asList(
+                "jsonize" // returns literal string "null"
+                ));
+        for (Entry<String, Function> entry : ControlFunctionRegistry.getFunctionMapping()) {
+            Function func = entry.getValue();
+            // No functions take 8 arguments, so they should all error
+            Object result = func.call(bindings, new Object[] {null, null, null, null, null, null, null, null});
+            if (returnsNull.contains(ControlFunctionRegistry.getFunctionName(func))) {
+                assertNull(result, ControlFunctionRegistry.getFunctionName(func) + " didn't return null on 8 args");
+            } else if (returnsFalse.contains(ControlFunctionRegistry.getFunctionName(func))) {
+                assertEquals(result, Boolean.FALSE, ControlFunctionRegistry.getFunctionName(func) + " didn't return false on 8 args");
+            } else if (!exempt.contains(ControlFunctionRegistry.getFunctionName(func))) {
+                assertTrue(result instanceof EvalError, ControlFunctionRegistry.getFunctionName(func) + " didn't error on 8 args");
+            }
+        }
+    }
 }
diff --git a/main/tests/server/src/com/google/refine/importers/JsonImporterTests.java b/main/tests/server/src/com/google/refine/importers/JsonImporterTests.java
index 65bcdf294..dc6740f41 100644
--- a/main/tests/server/src/com/google/refine/importers/JsonImporterTests.java
+++ b/main/tests/server/src/com/google/refine/importers/JsonImporterTests.java
@@ -639,7 +639,7 @@ public class JsonImporterTests extends ImporterTest {
     private String getComplexJSON(String fileName) throws IOException {
         InputStream in = this.getClass().getClassLoader()
                 .getResourceAsStream(fileName);
-        String content = org.apache.commons.io.IOUtils.toString(in);
+        String content = org.apache.commons.io.IOUtils.toString(in, "UTF-8");
         
         return content;
     }