Handle nanosecond normalization in IsoDuration

Database normalizes nanoseconds to be in range from 0 to 999_999_999.
`IsoDuration` previously did no calculations in it's `#toString()`
and returned incorrect result.

This commit makes it return correct string representation despite
normalized second and nanosecond components. It will also do
normalization in the constructor using
`java.time.Duration#ofSeconds(long, long)` in order to return correct
strings for durations created on the client side and not returned
from the database.

Author: lutovich

driver/src/main/java/org/neo4j/driver/internal/InternalIsoDuration.java

@@ -36,6 +36,7 @@
 
 public class InternalIsoDuration implements IsoDuration
 {
+    private static final long NANOS_PER_SECOND = 1_000_000_000;
     private static final List<TemporalUnit> SUPPORTED_UNITS = unmodifiableList( asList( MONTHS, DAYS, SECONDS, NANOS ) );
 
     private final long months;
@@ -45,25 +46,25 @@ public class InternalIsoDuration implements IsoDuration
 
     public InternalIsoDuration( Period period )
     {
-        this( period.toTotalMonths(), period.getDays(), 0, 0 );
+        this( period.toTotalMonths(), period.getDays(), Duration.ZERO );
     }
 
     public InternalIsoDuration( Duration duration )
     {
-        this( 0, 0, duration.getSeconds(), duration.getNano() );
+        this( 0, 0, duration );
     }
 
     public InternalIsoDuration( long months, long days, long seconds, int nanoseconds )
     {
-        this.months = months;
-        this.days = days;
-        this.seconds = seconds;
-        this.nanoseconds = nanoseconds;
+        this( months, days, Duration.ofSeconds( seconds, nanoseconds ) );
     }
 
-    public InternalIsoDuration( Period period, Duration duration )
+    InternalIsoDuration( long months, long days, Duration duration )
     {
-        this( period.toTotalMonths(), period.getDays(), duration.getSeconds(), duration.getNano() );
+        this.months = months;
+        this.days = days;
+        this.seconds = duration.getSeconds(); // normalized value of seconds
+        this.nanoseconds = duration.getNano(); // normalized value of nanoseconds in [0, 999_999_999]
     }
 
     @Override
@@ -192,8 +193,41 @@ public int hashCode()
     @Override
     public String toString()
     {
-        String secondsSign = seconds < 0 || nanoseconds < 0 ? "-" : "";
-        String nanosecondsString = nanoseconds == 0 ? "" : String.format( ".%09d", Math.abs( nanoseconds ) );
-        return String.format( "P%sM%sDT%s%s%sS", months, days, secondsSign, Math.abs( seconds ), nanosecondsString );
+        StringBuilder sb = new StringBuilder();
+        sb.append( 'P' );
+        sb.append( months ).append( 'M' );
+        sb.append( days ).append( 'D' );
+        sb.append( 'T' );
+        if ( seconds < 0 && nanoseconds > 0 )
+        {
+            if ( seconds == -1 )
+            {
+                sb.append( "-0" );
+            }
+            else
+            {
+                sb.append( seconds + 1 );
+            }
+        }
+        else
+        {
+            sb.append( seconds );
+        }
+        if ( nanoseconds > 0 )
+        {
+            int pos = sb.length();
+            // append nanoseconds as a 10-digit string with leading '1' that is later replaced by a '.'
+            if ( seconds < 0 )
+            {
+                sb.append( 2 * NANOS_PER_SECOND - nanoseconds );
+            }
+            else
+            {
+                sb.append( NANOS_PER_SECOND + nanoseconds );
+            }
+            sb.setCharAt( pos, '.' ); // replace '1' with '.'
+        }
+        sb.append( 'S' );
+        return sb.toString();
     }
 }

driver/src/test/java/org/neo4j/driver/internal/InternalIsoDurationTest.java

@@ -153,19 +153,36 @@ public void shouldCreateFromDuration()
     }
 
     @Test
-    public void toStringShouldPrintInIsoStandardFormat() throws Throwable
+    public void toStringShouldPrintInIsoStandardFormat()
     {
-        assertThat( new InternalIsoDuration( 0, 0, 0, 0 ).toString(), equalTo( "P0M0DT0S" ) );
-        assertThat( new InternalIsoDuration( 2, 45, 59, 11 ).toString(), equalTo( "P2M45DT59.000000011S" ) );
-        assertThat( new InternalIsoDuration( 4, -101, 1, 999 ).toString(), equalTo( "P4M-101DT1.000000999S" ) );
-        assertThat( new InternalIsoDuration( -1, 12, -19, 1 ).toString(), equalTo( "P-1M12DT-19.000000001S" ) );
+        assertThat( newDuration( 0, 0, 0, 0 ).toString(), equalTo( "P0M0DT0S" ) );
+        assertThat( newDuration( 2, 45, 59, 11 ).toString(), equalTo( "P2M45DT59.000000011S" ) );
+        assertThat( newDuration( 4, -101, 1, 999 ).toString(), equalTo( "P4M-101DT1.000000999S" ) );
+        assertThat( newDuration( -1, 12, -19, 1 ).toString(), equalTo( "P-1M12DT-18.999999999S" ) );
+        assertThat( newDuration( 0, 0, -1, 1 ).toString(), equalTo( "P0M0DT-0.999999999S" ) );
 
         assertThat( new InternalIsoDuration( Period.parse( "P356D" ) ).toString(), equalTo( "P0M356DT0S" ) );
         assertThat( new InternalIsoDuration( Duration.parse( "PT45S" ) ).toString(), equalTo( "P0M0DT45S" ) );
 
-        assertThat( new InternalIsoDuration( Period.parse( "P14D" ), Duration.parse( "PT16H12M" ) ).toString(), equalTo( "P0M14DT58320S" ) );
-        assertThat( new InternalIsoDuration( Period.parse( "P5M1D" ), Duration.parse( "PT12H" ) ).toString(), equalTo( "P5M1DT43200S" ) );
-        assertThat( new InternalIsoDuration( Period.parse( "P2W3D" ), Duration.parse( "PT2H0.111222333S" ) ).toString(), equalTo( "P0M17DT7200.111222333S" ) );
+        assertThat( new InternalIsoDuration( 0, 14, Duration.parse( "PT16H12M" ) ).toString(), equalTo( "P0M14DT58320S" ) );
+        assertThat( new InternalIsoDuration( 5, 1, Duration.parse( "PT12H" ) ).toString(), equalTo( "P5M1DT43200S" ) );
+        assertThat( new InternalIsoDuration( 0, 17, Duration.parse( "PT2H0.111222333S" ) ).toString(), equalTo( "P0M17DT7200.111222333S" ) );
+
+        assertThat( newDuration( 42, 42, 42, 0 ).toString(), equalTo( "P42M42DT42S" ) );
+        assertThat( newDuration( 42, 42, -42, 0 ).toString(), equalTo( "P42M42DT-42S" ) );
+
+        assertThat( newDuration( 42, 42, 0, 5 ).toString(), equalTo( "P42M42DT0.000000005S" ) );
+        assertThat( newDuration( 42, 42, 0, -5 ).toString(), equalTo( "P42M42DT-0.000000005S" ) );
+
+        assertThat( newDuration( 42, 42, 1, 5 ).toString(), equalTo( "P42M42DT1.000000005S" ) );
+        assertThat( newDuration( 42, 42, -1, 5 ).toString(), equalTo( "P42M42DT-0.999999995S" ) );
+        assertThat( newDuration( 42, 42, 1, -5 ).toString(), equalTo( "P42M42DT0.999999995S" ) );
+        assertThat( newDuration( 42, 42, -1, -5 ).toString(), equalTo( "P42M42DT-1.000000005S" ) );
+
+        assertThat( newDuration( 42, 42, 28, 9 ).toString(), equalTo( "P42M42DT28.000000009S" ) );
+        assertThat( newDuration( 42, 42, -28, 9 ).toString(), equalTo( "P42M42DT-27.999999991S" ) );
+        assertThat( newDuration( 42, 42, 28, -9 ).toString(), equalTo( "P42M42DT27.999999991S" ) );
+        assertThat( newDuration( 42, 42, -28, -9 ).toString(), equalTo( "P42M42DT-28.000000009S" ) );
     }
 
     private static IsoDuration newDuration( long months, long days, long seconds, int nanoseconds )