diff --git a/src/core/geometry/qgscircularstring.cpp b/src/core/geometry/qgscircularstring.cpp
index 7a5d1b1fceaf..42d42fa8792b 100644
--- a/src/core/geometry/qgscircularstring.cpp
+++ b/src/core/geometry/qgscircularstring.cpp
@@ -314,10 +314,18 @@ bool QgsCircularString::fromWkt( const QString &wkt )
     return false;
   mWkbType = parts.first;
 
-  if ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 )
+  parts.second = parts.second.remove( '(' ).remove( ')' );
+  QString secondWithoutParentheses = parts.second;
+  secondWithoutParentheses = secondWithoutParentheses.simplified().remove( ' ' );
+  if ( ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 ) ||
+       secondWithoutParentheses.isEmpty() )
     return true;
 
-  setPoints( QgsGeometryUtils::pointsFromWKT( parts.second, is3D(), isMeasure() ) );
+  QgsPointSequence points = QgsGeometryUtils::pointsFromWKT( parts.second, is3D(), isMeasure() );
+  if ( points.isEmpty() )
+    return false;
+
+  setPoints( points );
   return true;
 }
 
diff --git a/src/core/geometry/qgscompoundcurve.cpp b/src/core/geometry/qgscompoundcurve.cpp
index c1caf408ddb1..8f27f41cfd87 100644
--- a/src/core/geometry/qgscompoundcurve.cpp
+++ b/src/core/geometry/qgscompoundcurve.cpp
@@ -179,7 +179,10 @@ bool QgsCompoundCurve::fromWkt( const QString &wkt )
     return false;
   mWkbType = parts.first;
 
-  if ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 )
+  QString secondWithoutParentheses = parts.second;
+  secondWithoutParentheses = secondWithoutParentheses.remove( '(' ).remove( ')' ).simplified().remove( ' ' );
+  if ( ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 ) ||
+       secondWithoutParentheses.isEmpty() )
     return true;
 
   QString defaultChildWkbType = QStringLiteral( "LineString%1%2" ).arg( is3D() ? QStringLiteral( "Z" ) : QString(), isMeasure() ? QStringLiteral( "M" ) : QString() );
diff --git a/src/core/geometry/qgscurvepolygon.cpp b/src/core/geometry/qgscurvepolygon.cpp
index 1ff044ec55f2..7b62fb3261d4 100644
--- a/src/core/geometry/qgscurvepolygon.cpp
+++ b/src/core/geometry/qgscurvepolygon.cpp
@@ -215,7 +215,10 @@ bool QgsCurvePolygon::fromWkt( const QString &wkt )
 
   mWkbType = parts.first;
 
-  if ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 )
+  QString secondWithoutParentheses = parts.second;
+  secondWithoutParentheses = secondWithoutParentheses.remove( '(' ).remove( ')' ).simplified().remove( ' ' );
+  if ( ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 ) ||
+       secondWithoutParentheses.isEmpty() )
     return true;
 
   QString defaultChildWkbType = QStringLiteral( "LineString%1%2" ).arg( is3D() ? QStringLiteral( "Z" ) : QString(), isMeasure() ? QStringLiteral( "M" ) : QString() );
diff --git a/src/core/geometry/qgsgeometrycollection.cpp b/src/core/geometry/qgsgeometrycollection.cpp
index d6eb25debd3b..086497c8d787 100644
--- a/src/core/geometry/qgsgeometrycollection.cpp
+++ b/src/core/geometry/qgsgeometrycollection.cpp
@@ -698,7 +698,10 @@ bool QgsGeometryCollection::fromCollectionWkt( const QString &wkt, const QVector
   }
   mWkbType = parts.first;
 
-  if ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 )
+  QString secondWithoutParentheses = parts.second;
+  secondWithoutParentheses = secondWithoutParentheses.remove( '(' ).remove( ')' ).simplified().remove( ' ' );
+  if ( ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 ) ||
+       secondWithoutParentheses.isEmpty() )
     return true;
 
   QString defChildWkbType = QStringLiteral( "%1%2%3 " ).arg( defaultChildWkbType, is3D() ? QStringLiteral( "Z" ) : QString(), isMeasure() ? QStringLiteral( "M" ) : QString() );
diff --git a/src/core/geometry/qgsgeometryutils.cpp b/src/core/geometry/qgsgeometryutils.cpp
index ad7f3a28b1d3..d123d9bfd0ef 100644
--- a/src/core/geometry/qgsgeometryutils.cpp
+++ b/src/core/geometry/qgsgeometryutils.cpp
@@ -1100,15 +1100,22 @@ QgsPointSequence QgsGeometryUtils::pointsFromWKT( const QString &wktCoordinateLi
 {
   int dim = 2 + is3D + isMeasure;
   QgsPointSequence points;
+
   const QStringList coordList = wktCoordinateList.split( ',', QString::SkipEmptyParts );
 
   //first scan through for extra unexpected dimensions
   bool foundZ = false;
   bool foundM = false;
   QRegularExpression rx( QStringLiteral( "\\s" ) );
+  QRegularExpression rxIsNumber( QStringLiteral( "^[+-]?(\\d\\.?\\d*[Ee][+\\-]?\\d+|(\\d+\\.\\d*|\\d*\\.\\d+)|\\d+)$" ) );
   for ( const QString &pointCoordinates : coordList )
   {
     QStringList coordinates = pointCoordinates.split( rx, QString::SkipEmptyParts );
+
+    // exit with an empty set if one list contains invalid value.
+    if ( coordinates.filter( rxIsNumber ).size() != coordinates.size() )
+      return points;
+
     if ( coordinates.size() == 3 && !foundZ && !foundM && !is3D && !isMeasure )
     {
       // 3 dimensional coordinates, but not specifically marked as such. We allow this
@@ -1313,6 +1320,14 @@ QPair<QgsWkbTypes::Type, QString> QgsGeometryUtils::wktReadBlock( const QString
   }
   else
   {
+    const int openedParenthesisCount = wktParsed.count( '(' );
+    const int closedParenthesisCount = wktParsed.count( ')' );
+    // closes missing parentheses
+    for ( int i = 0 ;  i < openedParenthesisCount - closedParenthesisCount; ++i )
+      wktParsed.push_back( ')' );
+    // removes extra parentheses
+    wktParsed.truncate( wktParsed.size() - ( closedParenthesisCount - openedParenthesisCount ) );
+
     QRegularExpression cooRegEx( QStringLiteral( "^[^\\(]*\\((.*)\\)[^\\)]*$" ) );
     cooRegEx.setPatternOptions( QRegularExpression::DotMatchesEverythingOption );
     QRegularExpressionMatch match = cooRegEx.match( wktParsed );
diff --git a/src/core/geometry/qgslinestring.cpp b/src/core/geometry/qgslinestring.cpp
index 39bcfd4b5d0c..d6083ea286f1 100644
--- a/src/core/geometry/qgslinestring.cpp
+++ b/src/core/geometry/qgslinestring.cpp
@@ -434,10 +434,20 @@ bool QgsLineString::fromWkt( const QString &wkt )
     return false;
   mWkbType = parts.first;
 
-  if ( parts.second == "EMPTY" )
+  QString secondWithoutParentheses = parts.second;
+  secondWithoutParentheses = secondWithoutParentheses.remove( '(' ).remove( ')' ).simplified().remove( ' ' );
+  parts.second = parts.second.remove( '(' ).remove( ')' );
+  if ( ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 ) ||
+       secondWithoutParentheses.isEmpty() )
     return true;
 
-  setPoints( QgsGeometryUtils::pointsFromWKT( parts.second, is3D(), isMeasure() ) );
+  QgsPointSequence points = QgsGeometryUtils::pointsFromWKT( parts.second, is3D(), isMeasure() );
+  // There is a non number in the coordinates sequence
+  // LineString ( A b, 1 2)
+  if ( points.isEmpty() )
+    return false;
+
+  setPoints( points );
   return true;
 }
 
diff --git a/src/core/geometry/qgspoint.cpp b/src/core/geometry/qgspoint.cpp
index 48a7ceb8aa7b..f6d147a98b10 100644
--- a/src/core/geometry/qgspoint.cpp
+++ b/src/core/geometry/qgspoint.cpp
@@ -169,11 +169,31 @@ bool QgsPoint::fromWkt( const QString &wkt )
     return false;
   mWkbType = parts.first;
 
-  if ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 )
+  QString secondWithoutParentheses = parts.second;
+  secondWithoutParentheses = secondWithoutParentheses.remove( '(' ).remove( ')' ).simplified().remove( ' ' );
+  parts.second = parts.second.remove( '(' ).remove( ')' );
+  if ( ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 ) ||
+       secondWithoutParentheses.isEmpty() )
     return true;
 
   QRegularExpression rx( QStringLiteral( "\\s" ) );
   QStringList coordinates = parts.second.split( rx, QString::SkipEmptyParts );
+
+  // So far the parser hasn't looked at the coordinates. We'll avoid having anything but numbers and return NULL instead of 0 as a coordinate.
+  // Without this check, "POINT (a, b)" or "POINT (( 4, 3 ))" returned "POINT (0 ,0)"
+  // And some strange conversion...
+  // .. python:
+  // p = QgsPoint()
+  // p.fromWkt("POINT (-3.12, -4.2")
+  // False
+  // p.fromWkt( "POINT (-5.1234, -1.4321)" )
+  // True
+  // p.asWkt()
+  // 'Point (0 -1.43209999999999993)'
+  QRegularExpression rxIsNumber( QStringLiteral( "^[+-]?(\\d\\.?\\d*[Ee][+\\-]?\\d+|(\\d+\\.\\d*|\\d*\\.\\d+)|\\d+)$" ) );
+  if ( coordinates.filter( rxIsNumber ).size() != coordinates.size() )
+    return false;
+
   if ( coordinates.size() < 2 )
   {
     clear();
diff --git a/src/core/geometry/qgstriangle.cpp b/src/core/geometry/qgstriangle.cpp
index 86b5aa813229..6ee1dc291782 100644
--- a/src/core/geometry/qgstriangle.cpp
+++ b/src/core/geometry/qgstriangle.cpp
@@ -159,7 +159,6 @@ bool QgsTriangle::fromWkb( QgsConstWkbPtr &wkbPtr )
 
 bool QgsTriangle::fromWkt( const QString &wkt )
 {
-
   clear();
 
   QPair<QgsWkbTypes::Type, QString> parts = QgsGeometryUtils::wktReadBlock( wkt );
@@ -169,7 +168,10 @@ bool QgsTriangle::fromWkt( const QString &wkt )
 
   mWkbType = parts.first;
 
-  if ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 )
+  QString secondWithoutParentheses = parts.second;
+  secondWithoutParentheses = secondWithoutParentheses.simplified().remove( ' ' );
+  if ( ( parts.second.compare( QLatin1String( "EMPTY" ), Qt::CaseInsensitive ) == 0 ) ||
+       secondWithoutParentheses.isEmpty() )
     return true;
 
   QString defaultChildWkbType = QStringLiteral( "LineString%1%2" ).arg( is3D() ? QStringLiteral( "Z" ) : QString(), isMeasure() ? QStringLiteral( "M" ) : QString() );
@@ -200,6 +202,11 @@ bool QgsTriangle::fromWkt( const QString &wkt )
     return false;
   }
   mExteriorRing.reset( mInteriorRings.takeFirst() );
+  if ( ( mExteriorRing->numPoints() < 3 ) || ( mExteriorRing->numPoints() > 4 ) || ( mExteriorRing->numPoints() == 4 && mExteriorRing->startPoint() != mExteriorRing->endPoint() ) )
+  {
+    clear();
+    return false;
+  }
 
   //scan through rings and check if dimensionality of rings is different to CurvePolygon.
   //if so, update the type dimensionality of the CurvePolygon to match
diff --git a/tests/src/app/testqgsmaptooladdfeatureline.cpp b/tests/src/app/testqgsmaptooladdfeatureline.cpp
index c29f958bbd6a..b463fac1a796 100644
--- a/tests/src/app/testqgsmaptooladdfeatureline.cpp
+++ b/tests/src/app/testqgsmaptooladdfeatureline.cpp
@@ -212,7 +212,7 @@ void TestQgsMapToolAddFeatureLine::initTestCase()
 
   mLayerTopoZ->startEditing();
   QgsFeature topoFeat;
-  topoFeat.setGeometry( QgsGeometry::fromWkt( "MultiLineStringZ ((7.25 6 0, 7.25 7 0, 7.5 7 0, 7.5 6 0, 7.25 6 0),(6 6 0, 6 7 10, 7 7 0, 7 6 0, 6 6 0),(6.25 6.25 0, 6.75 6.25 0, 6.75 6.75 0, 6.25 6.75 0, 6.25 6.25 0)));" ) );
+  topoFeat.setGeometry( QgsGeometry::fromWkt( "MultiLineStringZ ((7.25 6 0, 7.25 7 0, 7.5 7 0, 7.5 6 0, 7.25 6 0),(6 6 0, 6 7 10, 7 7 0, 7 6 0, 6 6 0),(6.25 6.25 0, 6.75 6.25 0, 6.75 6.75 0, 6.25 6.75 0, 6.25 6.25 0))" ) );
 
   mLayerTopoZ->addFeature( topoFeat );
   QCOMPARE( mLayerTopoZ->featureCount(), ( long ) 1 );
diff --git a/tests/src/core/testqgsexpression.cpp b/tests/src/core/testqgsexpression.cpp
index 826b7ae53b6d..9533b1f8af4d 100644
--- a/tests/src/core/testqgsexpression.cpp
+++ b/tests/src/core/testqgsexpression.cpp
@@ -1262,27 +1262,27 @@ class TestQgsExpression: public QObject
       QTest::newRow( "is_multipart null" ) << "is_multipart(NULL)" << false << QVariant();
       QTest::newRow( "z_max no 3D" ) << "z_max(geom_from_wkt('POINT (0 0)'))" << false << QVariant();
       QTest::newRow( "z_max NULL" ) << "z_max(geom_from_wkt(NULL))" << false << QVariant();
-      QTest::newRow( "z_max point Z NaN" ) << "z_max(geom_from_wkt('PointZ (1 1 nan)'))" << false << QVariant( QVariant::Double );
-      QTest::newRow( "z_max line Z NaN" ) << "z_max(make_line(geom_from_wkt('PointZ (0 0 nan)'),make_point(-1,-1,-2)))" << false << QVariant( -2.0 );
       QTest::newRow( "z_max point" ) << "z_max(geom_from_wkt('POINT (0 0 1)'))" << false << QVariant( 1.0 );
+      QTest::newRow( "z_max point Z NaN" ) << "z_max(geom_from_wkt('PointZ (1 1 nan)'))" << false << QVariant( );
+      QTest::newRow( "z_max line Z NaN" ) << "z_max(make_line(geom_from_wkt('PointZ (0 0 nan)'),make_point(-1,-1,-2)))" << false << QVariant( );
       QTest::newRow( "z_max line" ) << "z_max(make_line(make_point(0,0,0),make_point(-1,-1,-2)))" << false << QVariant( 0.0 );
       QTest::newRow( "z_min no 3D" ) << "z_min(geom_from_wkt('POINT (0 0)'))" << false << QVariant();
       QTest::newRow( "z_min NULL" ) << "z_min(geom_from_wkt(NULL))" << false << QVariant();
-      QTest::newRow( "z_min point Z NaN" ) << "z_min(geom_from_wkt('PointZ (1 1 nan)'))" << false << QVariant( QVariant::Double );
-      QTest::newRow( "z_min line Z NaN" ) << "z_min(make_line(geom_from_wkt('PointZ (0 0 nan)'),make_point(-1,-1,-2)))" << false << QVariant( -2.0 );
       QTest::newRow( "z_min point" ) << "z_min(geom_from_wkt('POINT (0 0 1)'))" << false << QVariant( 1.0 );
+      QTest::newRow( "z_min point Z NaN" ) << "z_min(geom_from_wkt('PointZ (1 1 nan)'))" << false << QVariant( );
+      QTest::newRow( "z_min line Z NaN" ) << "z_min(make_line(geom_from_wkt('PointZ (0 0 nan)'),make_point(-1,-1,-2)))" << false << QVariant( );
       QTest::newRow( "z_min line" ) << "z_min(make_line(make_point(0,0,0),make_point(-1,-1,-2)))" << false << QVariant( -2.0 );
       QTest::newRow( "m_max no measure" ) << "m_max(geom_from_wkt('POINT (0 0)'))" << false << QVariant();
       QTest::newRow( "m_max NULL" ) << "m_max(geom_from_wkt(NULL))" << false << QVariant();
-      QTest::newRow( "m_max point M NaN" ) << "m_max(geom_from_wkt('PointZM (0 0 0 nan)'))" << false << QVariant( QVariant::Double );
-      QTest::newRow( "m_max line M NaN" ) << "m_max(make_line(geom_from_wkt('PointZM (0 0 0 nan)'),geom_from_wkt('PointZM (1 1 1 2)')))" << false << QVariant( 2.0 );
       QTest::newRow( "m_max point" ) << "m_max(make_point_m(0,0,1))" << false << QVariant( 1.0 );
+      QTest::newRow( "m_max point M NaN" ) << "m_max(geom_from_wkt('PointZM (0 0 0 nan)'))" << false << QVariant( );
+      QTest::newRow( "m_max line M NaN" ) << "m_max(make_line(geom_from_wkt('PointZM (0 0 0 nan)'),geom_from_wkt('PointZM (1 1 1 2)')))" << false << QVariant( );
       QTest::newRow( "m_max line" ) << "m_max(make_line(make_point_m(0,0,1),make_point_m(-1,-1,2),make_point_m(-2,-2,0)))" << false << QVariant( 2.0 );
       QTest::newRow( "m_min no measure" ) << "m_min(geom_from_wkt('POINT (0 0)'))" << false << QVariant();
       QTest::newRow( "m_min NULL" ) << "m_min(geom_from_wkt(NULL))" << false << QVariant();
-      QTest::newRow( "m_min point M NaN" ) << "m_min(geom_from_wkt('PointZM (0 0 0 nan)'))" << false << QVariant( QVariant::Double );
-      QTest::newRow( "m_min line M NaN" ) << "m_min(make_line(geom_from_wkt('PointZM (0 0 0 nan)'),geom_from_wkt('PointZM (1 1 1 2)')))" << false << QVariant( 2.0 );
       QTest::newRow( "m_min point" ) << "m_min(make_point_m(0,0,1))" << false << QVariant( 1.0 );
+      QTest::newRow( "m_min point M NaN" ) << "m_min(geom_from_wkt('PointZM (0 0 0 nan)'))" << false << QVariant( );
+      QTest::newRow( "m_min line M NaN" ) << "m_min(make_line(geom_from_wkt('PointZM (0 0 0 nan)'),geom_from_wkt('PointZM (1 1 1 2)')))" << false << QVariant( );
       QTest::newRow( "m_min line" ) << "m_min(make_line(make_point_m(0,0,1),make_point_m(-1,-1,2),make_point_m(-2,-2,0)))" << false << QVariant( 0.0 );
       QTest::newRow( "main angle polygon" ) << "round(main_angle( geom_from_wkt('POLYGON((0 0,2 9,9 2,0 0))')))" << false << QVariant( 77 );
       QTest::newRow( "main angle multi polygon" ) << "round(main_angle( geom_from_wkt('MULTIPOLYGON(((0 0,3 10,1 10,1 6,0 0)))')))" << false << QVariant( 17 );
diff --git a/tests/src/core/testqgsgeometry.cpp b/tests/src/core/testqgsgeometry.cpp
index 788c5fe98ea1..cfc7917fdf7d 100644
--- a/tests/src/core/testqgsgeometry.cpp
+++ b/tests/src/core/testqgsgeometry.cpp
@@ -164,6 +164,8 @@ class TestQgsGeometry : public QObject
 
     void testRandomPointsInPolygon();
 
+    void wktParser();
+
   private:
     //! Must be called before each render test
     void initPainterTest();
@@ -17504,7 +17506,7 @@ void TestQgsGeometry::makeValid()
                       QStringLiteral( "GEOMETRYCOLLECTION(POLYGON((0 0, 0 1, 1 1, 1 0, 0 0)), LINESTRING(0 0, -1 0))" ) );
   // collection with invalid geometries
   geoms << qMakePair( QStringLiteral( "GEOMETRYCOLLECTION(LINESTRING(0 0, 0 0), POLYGON((0 0, 10 10, 10 0, 0 10, 0 0)), LINESTRING(10 0, 10 10))" ),
-                      QStringLiteral( "GEOMETRYCOLLECTION(POINT(0 0), MULTIPOLYGON(((5 5, 0 0, 0 10, 5 5)),((5 5, 10 10, 10 0, 5 5))), LINESTRING(10 0, 10 10)))" ) );
+                      QStringLiteral( "GEOMETRYCOLLECTION(POINT(0 0), MULTIPOLYGON(((5 5, 0 0, 0 10, 5 5)),((5 5, 10 10, 10 0, 5 5))), LINESTRING(10 0, 10 10))" ) );
   // null line (#18077)
   geoms << qMakePair( QStringLiteral( "MultiLineString ((356984.0625 6300089, 356984.0625 6300089))" ),
                       QStringLiteral( "MultiPoint ((356984.0625 6300089))" ) );
@@ -18097,5 +18099,266 @@ void TestQgsGeometry::testRandomPointsInPolygon()
   QVERIFY( foundp2Point );
 }
 
+void TestQgsGeometry::wktParser()
+{
+  // POINT
+  // unbalanced parentheses
+  QVERIFY( QgsPoint().fromWkt( "POINT((0 1)" ) );
+  QVERIFY( QgsPoint().fromWkt( "POINT(0 1) )" ) );
+  QVERIFY( QgsPoint().fromWkt( "POINT ((0 1)" ) );
+  QVERIFY( QgsPoint().fromWkt( "POINT (0 1) )" ) );
+  // extra parentheses
+  QVERIFY( QgsPoint().fromWkt( "POINT ( (5 1) )" ) );
+  // not a number
+  QVERIFY( ! QgsPoint().fromWkt( "POINT (a, b)" ) );
+  QVERIFY( ! QgsPoint().fromWkt( "POINT (a b)" ) );
+  QVERIFY( ! QgsPoint().fromWkt( "POINT((0, 1)" ) );
+  QVERIFY( ! QgsPoint().fromWkt( "POINT(0, 1) )" ) );
+  QVERIFY( ! QgsPoint().fromWkt( "POINT ((0, 1)" ) );
+  QVERIFY( ! QgsPoint().fromWkt( "POINT (0, 1) )" ) );
+  QVERIFY( ! QgsPoint().fromWkt( "POINT ( (5, 1) )" ) );
+
+  // valid
+  QgsPoint p;
+  QVERIFY( p.fromWkt( "POINT (5 1)" ) );
+  QCOMPARE( p.asWkt(), QStringLiteral( "Point (5 1)" ) );
+  // extra parentheses
+  QVERIFY( p.fromWkt( "POINT ( (5 1) )" ) );
+  // unbalanced parentheses
+  QVERIFY( p.fromWkt( "POINT ( (5 1)" ) );
+  QCOMPARE( p.asWkt(), QStringLiteral( "Point (5 1)" ) );
+  QVERIFY( p.fromWkt( "POINT (5 1) )" ) );
+  QCOMPARE( p.asWkt(), QStringLiteral( "Point (5 1)" ) );
+
+  QVERIFY( p.fromWkt( "POINT (5.1234 1.4321)" ) );
+  QCOMPARE( p.asWkt( 4 ), QStringLiteral( "Point (5.1234 1.4321)" ) );
+  QVERIFY( p.fromWkt( "POINT (-5.1234 -1.4321)" ) );
+  QCOMPARE( p.asWkt( 4 ), QStringLiteral( "Point (-5.1234 -1.4321)" ) );
+  QVERIFY( p.fromWkt( "POINT (-12e4 -1.4e-1)" ) );
+  QCOMPARE( p.asWkt( 2 ), QStringLiteral( "Point (-120000 -0.14)" ) );
+
+  QVERIFY( p.fromWkt( "POINT ( )" ) );
+  QCOMPARE( p.asWkt(), QStringLiteral( "Point EMPTY" ) );
+  QVERIFY( ! p.fromWkt( "POINT (a, b)" ) );
+  QCOMPARE( p.asWkt(), QStringLiteral( "Point EMPTY" ) );
+  // LINESTRING
+  QVERIFY( QgsLineString().fromWkt( "LineString(0 1, 1 2) )" ) );
+  QVERIFY( QgsLineString().fromWkt( "LineString (0 1, 1 2) )" ) );
+  QVERIFY( QgsLineString().fromWkt( "LineString ( (0 1) )" ) );
+  QVERIFY( QgsLineString().fromWkt( "LineString ( ( 0 1, 2 3 ) )" ) );
+  QVERIFY( QgsMultiLineString().fromWkt( "MULTILINESTRING ((((1 2, 2 4, 4 5))" ) );
+  QVERIFY( QgsMultiLineString().fromWkt( "MULTILINESTRING((((1 2, 2 4, 4 5))" ) );
+  // not a number
+  QVERIFY( ! QgsLineString().fromWkt( "LineString(0, 1) )" ) );
+  QVERIFY( ! QgsLineString().fromWkt( "LineString (0, 1) )" ) );
+  QVERIFY( ! QgsLineString().fromWkt( "LineString (a b, 3 4)" ) );
+  QVERIFY( ! QgsMultiLineString().fromWkt( "MULTILINESTRING ((1 2, 2 a, 4 b))" ) );
+  // valid
+  QgsLineString l;
+  QVERIFY( l.fromWkt( "LINESTRING ( 1 2, 3 4 )" ) );
+  QCOMPARE( l.asWkt(), QStringLiteral( "LineString (1 2, 3 4)" ) );
+  // unbalanced parentheses
+  QVERIFY( l.fromWkt( "LINESTRING ( ( 1 2, 3 4 )" ) );
+  QCOMPARE( l.asWkt(), QStringLiteral( "LineString (1 2, 3 4)" ) );
+  QVERIFY( l.fromWkt( "LINESTRING ( 1 2, 3 4 ) )" ) );
+  QCOMPARE( l.asWkt(), QStringLiteral( "LineString (1 2, 3 4)" ) );
+  // extra parentheses
+  QVERIFY( l.fromWkt( "LINESTRING( ( 1 2, 3 4 ) )" ) );
+  QCOMPARE( l.asWkt(), QStringLiteral( "LineString (1 2, 3 4)" ) );
+  // empty
+  QVERIFY( l.fromWkt( "LINESTRING (  )" ) );
+  QCOMPARE( l.asWkt(), QStringLiteral( "LineString EMPTY" ) );
+  QVERIFY( ! l.fromWkt( "LINESTRING ( a b, 2 3  )" ) );
+  QCOMPARE( l.asWkt(), QStringLiteral( "LineString EMPTY" ) );
+  QVERIFY( l.fromWkt( "LINESTRING ( 1e4 -2, 3 +4.5 )" ) );
+  QCOMPARE( l.asWkt( 1 ), QStringLiteral( "LineString (10000 -2, 3 4.5)" ) );
+  QgsMultiLineString m;
+  m.fromWkt( "MULTILINESTRING ((1 2, 2 3, 4 5))" ) ;
+  QVERIFY( m.fromWkt( "MULTILINESTRING ((1 2, 2 3, 4 5))" ) );
+  QCOMPARE( m.asWkt( 1 ), QStringLiteral( "MultiLineString ((1 2, 2 3, 4 5))" ) );
+
+  // TRIANGLE
+  // unbalanced parenthesis
+  QVERIFY( QgsTriangle().fromWkt( "Triangle( (0 1, 1 2, 3 3) )) " ) );
+  QVERIFY( QgsTriangle().fromWkt( "Triangle ( (0 1, 1 2, 3 3) )) " ) );
+  QVERIFY( ! QgsTriangle().fromWkt( "Triangle(0 1, 1 2, 3 3) )" ) );
+  QVERIFY( ! QgsTriangle().fromWkt( "Triangle (0 1, 1 2, 3 3) )" ) );
+  // not a number
+  QVERIFY( ! QgsTriangle().fromWkt( "Triangle ( (0 a, b 2, 3 3 )) " ) );
+  QVERIFY( ! QgsTriangle().fromWkt( "Triangle ( (0 a, b 2, 3 3, 0 a )) " ) );
+  // incorrect number of points
+  QVERIFY( ! QgsTriangle().fromWkt( "Triangle (( 0 0, 1 1))" ) );
+  QVERIFY( ! QgsTriangle().fromWkt( "Triangle (( 0 0, 1 1, 1 0, 2 3, 4 5))" ) );
+  QVERIFY( ! QgsTriangle().fromWkt( "Triangle (( 0 1, 2 3, 3 4, 1 0))" ) ); // four points but start and last points are differents
+  // valid
+  QgsTriangle t;
+  QVERIFY( t.fromWkt( "TRIANGLE(( 0 1, 2 3, 3 4))" ) );
+  QCOMPARE( t.asWkt(), QStringLiteral( "Triangle ((0 1, 2 3, 3 4))" ) );
+  QVERIFY( t.fromWkt( "TRIANGLE(( 0 1, 2 3, 3 4, 0 1))" ) );
+  QCOMPARE( t.asWkt(), QStringLiteral( "Triangle ((0 1, 2 3, 3 4, 0 1))" ) );
+  QVERIFY( t.fromWkt( "TRIANGLE(( 0 1, 2 3, 3 4, 0 1))" ) );
+  QCOMPARE( t.asWkt(), QStringLiteral( "Triangle ((0 1, 2 3, 3 4, 0 1))" ) );
+  QVERIFY( ! t.fromWkt( "TRIANGLE(( 0 1, 2 3, 3 4, 0 3))" ) );
+  QCOMPARE( t.asWkt(), QStringLiteral( "Triangle EMPTY" ) );
+  QVERIFY( ! t.fromWkt( "TRIANGLE(( 0 1, 2 3, 3 4, 0 3, 4 5))" ) );
+  QCOMPARE( t.asWkt(), QStringLiteral( "Triangle EMPTY" ) );
+  QVERIFY( ! t.fromWkt( "TRIANGLE(( 0 1, 2 3 ))" ) );
+  QCOMPARE( t.asWkt(), QStringLiteral( "Triangle EMPTY" ) );
+  QVERIFY( t.fromWkt( "TRIANGLE((0 1e3, -2 3, +3 4, 0 1e3))" ) );
+  QCOMPARE( t.asWkt(), QStringLiteral( "Triangle ((0 1000, -2 3, 3 4, 0 1000))" ) );
+
+  // POLYGON
+  // unbalanced parenthesis
+  QVERIFY( QgsPolygon().fromWkt( "Polygon( (0 1, 1 2, 3 3) )) " ) );
+  QVERIFY( QgsPolygon().fromWkt( "Polygon ( (0 1, 1 2, 3 3) )) " ) );
+  QVERIFY( ! QgsPolygon().fromWkt( "Polygon(0 1, 1 2, 3 3) )" ) );
+  QVERIFY( ! QgsPolygon().fromWkt( "Polygon (0 1, 1 2, 3 3) )" ) );
+  // not a number
+  QVERIFY( ! QgsPolygon().fromWkt( "Polygon ( (0 a, b 2, 3 3 )) " ) );
+  QVERIFY( ! QgsPolygon().fromWkt( "Polygon ( (0 a, b 2, 3 3, 0 a )) " ) );
+  // valid
+  QgsPolygon poly;
+  QVERIFY( poly.fromWkt( "Polygon(( 0 1, 2 3, 3 4))" ) );
+  QCOMPARE( poly.asWkt(), QStringLiteral( "Polygon ((0 1, 2 3, 3 4))" ) ); // TODO: A polygon must be closed
+  QVERIFY( poly.fromWkt( "Polygon(( 0 1, 2 3, 3 4, 0 1))" ) );
+  QCOMPARE( poly.asWkt(), QStringLiteral( "Polygon ((0 1, 2 3, 3 4, 0 1))" ) );
+  QVERIFY( poly.fromWkt( "Polygon((0 1e3, -2 3, +3 4, 0 1))" ) );
+  QCOMPARE( poly.asWkt(), QStringLiteral( "Polygon ((0 1000, -2 3, 3 4, 0 1))" ) );
+
+  // Circular string
+  // unbalanced parenthesis
+  QVERIFY( QgsCircularString().fromWkt( "CircularString(0 1, 1 2, 3 3) )" ) );
+  QVERIFY( QgsCircularString().fromWkt( "CircularString (0 1, 1 2, 3 3) )" ) );
+  QVERIFY( QgsCircularString().fromWkt( "CircularString( (0 1, 1 2, 3 3) )) " ) );
+  QVERIFY( QgsCircularString().fromWkt( "CircularString ( (0 1, 1 2, 3 3) )) " ) );
+  // not a number
+  QVERIFY( ! QgsCircularString().fromWkt( "CircularString (0 a, b 2, 3 3) " ) );
+  QVERIFY( ! QgsCircularString().fromWkt( "CircularString (0 a, b 2, 3 3, 0 a) " ) );
+  // valid
+  QgsCircularString c;
+  QVERIFY( c.fromWkt( "CircularString( 0 1, 2 3, 3 4)" ) );
+  QCOMPARE( c.asWkt(), QStringLiteral( "CircularString (0 1, 2 3, 3 4)" ) );
+  QVERIFY( c.fromWkt( "CircularString(0 1e3, -2 3, +3 4)" ) );
+  QCOMPARE( c.asWkt(), QStringLiteral( "CircularString (0 1000, -2 3, 3 4)" ) );
+
+  QVERIFY( c.fromWkt( "CircularString ((0 0,1 1,2 0))" ) ); // Added from an old test with an invalid wkt, but allowed in QGIS https://github.com/qgis/QGIS/pull/38439/files/59aab9dc9cc58bdc98e6d8091840bc129564ed2f#diff-fe3aa1328ee04f0eb00a1b1d59c0ea71L4247
+  QCOMPARE( c.asWkt(), QStringLiteral( "CircularString (0 0, 1 1, 2 0)" ) );
+
+  // multipoint
+  QgsMultiPoint mp;
+  QVERIFY( ! mp.fromWkt( "MULTIPOINT (((10 40), (40 30), (20 20), (30 10))" ) );
+  QVERIFY( ! mp.fromWkt( "MULTIPOINT (((10 40), (40 30), (xx20 20), (30 10))" ) );
+  QVERIFY( ! mp.fromWkt( "MULTIPOINT ((10 40, 40 30, 20 20, 30 10)" ) );
+  QVERIFY( mp.fromWkt( "MULTIPOINT ((10 40), (40 30), (20 20), (30 10))))" ) );
+  QVERIFY( mp.fromWkt( "MULTIPOINT ( )" ) );
+  QVERIFY( mp.fromWkt( "MULTIPOINT EMPTY" ) );
+  QVERIFY( mp.fromWkt( "MULTIPOINT ((10 40), (40 30), (20 20), (30 10))" ) );
+  QCOMPARE( mp.asWkt(), QStringLiteral( "MultiPoint ((10 40),(40 30),(20 20),(30 10))" ) );
+  QVERIFY( mp.fromWkt( "MULTIPOINT (10 40, 40 30, 20 20, 30 10)" ) );
+  QCOMPARE( mp.asWkt(), QStringLiteral( "MultiPoint ((10 40),(40 30),(20 20),(30 10))" ) );
+  QVERIFY( mp.fromWkt( "MULTIPOINT ((10 40), (40 30), (20 20), (30 10))))" ) );
+  QCOMPARE( mp.asWkt(), QStringLiteral( "MultiPoint ((10 40),(40 30),(20 20),(30 10))" ) );
+  QVERIFY( mp.fromWkt( "MULTIPOINT ( )" ) );
+  QCOMPARE( mp.asWkt(), QStringLiteral( "MultiPoint EMPTY" ) );
+  QVERIFY( mp.fromWkt( "MULTIPOINT EMPTY" ) );
+  QCOMPARE( mp.asWkt(), QStringLiteral( "MultiPoint EMPTY" ) );
+  // Added from an old test with an invalid wkt, but allowed in QGIS https://github.com/qgis/QGIS/pull/38439/files/59aab9dc9cc58bdc98e6d8091840bc129564ed2f#diff-4444b5a772b35be43721b71a4b95d785R50
+  QVERIFY( mp.fromWkt( "MULTIPOINT(0 20,20 20))" ) );
+  QCOMPARE( mp.asWkt(), QStringLiteral( "MultiPoint ((0 20),(20 20))" ) );
+
+  // compoundcurve
+  QgsCompoundCurve cc;
+  QVERIFY( ! cc.fromWkt( "COMPOUNDCURVE((CIRCULARSTRING( 0 0, 1 1, 2 2))" ) );
+  QVERIFY( cc.fromWkt( "COMPOUNDCURVE(CIRCULARSTRING( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( cc.asWkt(), QStringLiteral( "CompoundCurve (CircularString (0 0, 1 1, 2 2))" ) );
+  QVERIFY( cc.fromWkt( "COMPOUNDCURVE(CIRCULARSTRING( 0 0, 1 1, 2 2))" ) );
+  QCOMPARE( cc.asWkt(), QStringLiteral( "CompoundCurve (CircularString (0 0, 1 1, 2 2))" ) );
+  QVERIFY( cc.fromWkt( "COMPOUNDCURVE(CIRCULARSTRING( 0 0, 1 1, 2 2), LINESTRING((2 2, 3 3)))" ) );
+  QCOMPARE( cc.asWkt(), QStringLiteral( "CompoundCurve (CircularString (0 0, 1 1, 2 2),(2 2, 3 3))" ) );
+  QVERIFY( cc.fromWkt( "COMPOUNDCURVE ( )" ) );
+  QCOMPARE( cc.asWkt(), QStringLiteral( "CompoundCurve EMPTY" ) );
+  QVERIFY( cc.fromWkt( "COMPOUNDCURVE EMPTY" ) );
+  QCOMPARE( cc.asWkt(), QStringLiteral( "CompoundCurve EMPTY" ) );
+  // geometrycollection
+  QgsGeometryCollection gc;
+  QVERIFY( gc.fromWkt( "GeometryCollection((CIRCULARSTRING( 0 0, 1 1, 2 2))" ) );
+  QCOMPARE( gc.asWkt(), QStringLiteral( "GeometryCollection (GeometryCollection (CircularString (0 0, 1 1, 2 2)))" ) );
+  QVERIFY( gc.fromWkt( "GeometryCollection(CIRCULARSTRING( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( gc.asWkt(), QStringLiteral( "GeometryCollection (CircularString (0 0, 1 1, 2 2))" ) );
+  QVERIFY( gc.fromWkt( "GeometryCollection(CIRCULARSTRING( 0 0, 1 1, 2 2))" ) );
+  QCOMPARE( gc.asWkt(), QStringLiteral( "GeometryCollection (CircularString (0 0, 1 1, 2 2))" ) );
+  QVERIFY( gc.fromWkt( "GeometryCollection(CIRCULARSTRING( 0 0, 1 1, 2 2), LINESTRING((2 2, 3 3)))" ) );
+  QCOMPARE( gc.asWkt(), QStringLiteral( "GeometryCollection (CircularString (0 0, 1 1, 2 2),LineString (2 2, 3 3))" ) );
+  QVERIFY( gc.fromWkt( "GeometryCollection ( )" ) );
+  QCOMPARE( gc.asWkt(), QStringLiteral( "GeometryCollection EMPTY" ) );
+  QVERIFY( gc.fromWkt( "GeometryCollection EMPTY" ) );
+  QCOMPARE( gc.asWkt(), QStringLiteral( "GeometryCollection EMPTY" ) );
+  // curvepolygon
+  QgsCurvePolygon cp;
+  QVERIFY( ! cp.fromWkt( "CurvePolygon((CIRCULARSTRING( 0 0, 1 1, 2 2))" ) );
+  QVERIFY( cp.fromWkt( "CurvePolygon(CIRCULARSTRING( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( cp.asWkt(), QStringLiteral( "CurvePolygon (CircularString (0 0, 1 1, 2 2))" ) );
+  QVERIFY( cp.fromWkt( "CurvePolygon(CIRCULARSTRING( 0 0, 1 1, 2 2))" ) );
+  QCOMPARE( cp.asWkt(), QStringLiteral( "CurvePolygon (CircularString (0 0, 1 1, 2 2))" ) );
+  QVERIFY( cp.fromWkt( "CurvePolygon(CIRCULARSTRING( 0 0, 1 1, 2 2), LINESTRING((2 2, 3 3)))" ) );
+  QCOMPARE( cp.asWkt(), QStringLiteral( "CurvePolygon (CircularString (0 0, 1 1, 2 2),(2 2, 3 3))" ) );
+  QVERIFY( cp.fromWkt( "CurvePolygon ( )" ) );
+  QCOMPARE( cp.asWkt(), QStringLiteral( "CurvePolygon EMPTY" ) );
+  QVERIFY( cp.fromWkt( "CurvePolygon EMPTY" ) );
+  QCOMPARE( cp.asWkt(), QStringLiteral( "CurvePolygon EMPTY" ) );
+  // multicurve
+  QgsMultiCurve mc;
+  QVERIFY( ! mc.fromWkt( "MultiCurve((CIRCULARSTRING( 0 0, 1 1, 2 2))" ) );
+  QVERIFY( mc.fromWkt( "MultiCurve(CIRCULARSTRING( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( mc.asWkt(), QStringLiteral( "MultiCurve (CircularString (0 0, 1 1, 2 2))" ) );
+  QVERIFY( mc.fromWkt( "MultiCurve(CIRCULARSTRING( 0 0, 1 1, 2 2))" ) );
+  QCOMPARE( mc.asWkt(), QStringLiteral( "MultiCurve (CircularString (0 0, 1 1, 2 2))" ) );
+  QVERIFY( mc.fromWkt( "MultiCurve(CIRCULARSTRING( 0 0, 1 1, 2 2), LINESTRING((2 2, 3 3)))" ) );
+  QCOMPARE( mc.asWkt(), QStringLiteral( "MultiCurve (CircularString (0 0, 1 1, 2 2),LineString (2 2, 3 3))" ) );
+  QVERIFY( mc.fromWkt( "MultiCurve ( )" ) );
+  QCOMPARE( mc.asWkt(), QStringLiteral( "MultiCurve EMPTY" ) );
+  QVERIFY( mc.fromWkt( "MultiCurve EMPTY" ) );
+  QCOMPARE( mc.asWkt(), QStringLiteral( "MultiCurve EMPTY" ) );
+  // multisurface
+  QgsMultiSurface ms;
+  QVERIFY( ! ms.fromWkt( "MultiSurface((Polygon( 0 0, 1 1, 2 2))" ) );
+  QVERIFY( ms.fromWkt( "MultiSurface(Polygon(( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( ms.asWkt(), QStringLiteral( "MultiSurface (Polygon ((0 0, 1 1, 2 2)))" ) );
+  QVERIFY( ms.fromWkt( "MultiSurface(Polygon(( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( ms.asWkt(), QStringLiteral( "MultiSurface (Polygon ((0 0, 1 1, 2 2)))" ) );
+  QVERIFY( ms.fromWkt( "MultiSurface(Polygon(( 0 0, 1 1, 2 2)), Polygon((2 2, 3 3, 3 2)))" ) );
+  QCOMPARE( ms.asWkt(), QStringLiteral( "MultiSurface (Polygon ((0 0, 1 1, 2 2)),Polygon ((2 2, 3 3, 3 2)))" ) );
+  QVERIFY( ms.fromWkt( "MultiSurface ( )" ) );
+  QCOMPARE( ms.asWkt(), QStringLiteral( "MultiSurface EMPTY" ) );
+  QVERIFY( ms.fromWkt( "MultiSurface EMPTY" ) );
+  QCOMPARE( ms.asWkt(), QStringLiteral( "MultiSurface EMPTY" ) );
+  // multipolygon
+  QgsMultiPolygon mpoly;
+  QVERIFY( ! mpoly.fromWkt( "MultiPolygon((Polygon( 0 0, 1 1, 2 2))" ) );
+  QVERIFY( mpoly.fromWkt( "MultiPolygon(Polygon(( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( mpoly.asWkt(), QStringLiteral( "MultiPolygon (((0 0, 1 1, 2 2)))" ) );
+  QVERIFY( mpoly.fromWkt( "MultiPolygon(Polygon(( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( mpoly.asWkt(), QStringLiteral( "MultiPolygon (((0 0, 1 1, 2 2)))" ) );
+  QVERIFY( mpoly.fromWkt( "MultiPolygon(Polygon(( 0 0, 1 1, 2 2)), Polygon((2 2, 3 3, 3 2)))" ) );
+  QCOMPARE( mpoly.asWkt(), QStringLiteral( "MultiPolygon (((0 0, 1 1, 2 2)),((2 2, 3 3, 3 2)))" ) );
+  QVERIFY( mpoly.fromWkt( "MultiPolygon ( )" ) );
+  QCOMPARE( mpoly.asWkt(), QStringLiteral( "MultiPolygon EMPTY" ) );
+  QVERIFY( mpoly.fromWkt( "MultiPolygon EMPTY" ) );
+  QCOMPARE( mpoly.asWkt(), QStringLiteral( "MultiPolygon EMPTY" ) );
+
+  // multilinestring
+  QgsMultiLineString mline;
+  QVERIFY( ! mline.fromWkt( "MultiLineString((LineString( 0 0, 1 1, 2 2))" ) );
+  QVERIFY( mline.fromWkt( "MultiLineString(LineString(( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( mline.asWkt(), QStringLiteral( "MultiLineString ((0 0, 1 1, 2 2))" ) );
+  QVERIFY( mline.fromWkt( "MultiLineString(LineString(( 0 0, 1 1, 2 2)))" ) );
+  QCOMPARE( mline.asWkt(), QStringLiteral( "MultiLineString ((0 0, 1 1, 2 2))" ) );
+  QVERIFY( mline.fromWkt( "MultiLineString(LineString(( 0 0, 1 1, 2 2)), LineString((2 2, 3 3, 3 2)))" ) );
+  QCOMPARE( mline.asWkt(), QStringLiteral( "MultiLineString ((0 0, 1 1, 2 2),(2 2, 3 3, 3 2))" ) );
+  QVERIFY( mline.fromWkt( "MultiLineString ( )" ) );
+  QCOMPARE( mline.asWkt(), QStringLiteral( "MultiLineString EMPTY" ) );
+  QVERIFY( mline.fromWkt( "MultiLineString EMPTY" ) );
+  QCOMPARE( mline.asWkt(), QStringLiteral( "MultiLineString EMPTY" ) );
+}
 QGSTEST_MAIN( TestQgsGeometry )
 #include "testqgsgeometry.moc"
diff --git a/tests/src/python/test_provider_ogr_gpkg.py b/tests/src/python/test_provider_ogr_gpkg.py
index a2de092e3031..22b4831f8a36 100644
--- a/tests/src/python/test_provider_ogr_gpkg.py
+++ b/tests/src/python/test_provider_ogr_gpkg.py
@@ -320,7 +320,7 @@ def testCurveGeometryType(self):
         vl.dataProvider().addFeatures([f])
         got = [feat for feat in vl.getFeatures()][0]
         got_geom = got.geometry()
-        reference = QgsGeometry.fromWkt('CurvePolygon (((0 0, 0 1, 1 1, 0 0)))')
+        reference = QgsGeometry.fromWkt('CurvePolygon ((0 0, 0 1, 1 1, 0 0))')
         # The geometries must be binarily identical
         self.assertEqual(got_geom.asWkb(), reference.asWkb(),
                          'Expected {}, got {}'.format(reference.asWkt(), got_geom.asWkt()))
diff --git a/tests/src/python/test_qgsdistancearea.py b/tests/src/python/test_qgsdistancearea.py
index fadcc2df0a70..12c7e4a022a1 100644
--- a/tests/src/python/test_qgsdistancearea.py
+++ b/tests/src/python/test_qgsdistancearea.py
@@ -984,7 +984,7 @@ def testSplitGeometryAtAntimeridian(self):
         self.assertEqual(g.asWkt(), 'PointZ (1 2 3)')
         g = da.splitGeometryAtAntimeridian(QgsGeometry.fromWkt('PointM(1 2 3)'))
         self.assertEqual(g.asWkt(), 'PointM (1 2 3)')
-        g = da.splitGeometryAtAntimeridian(QgsGeometry.fromWkt('LineString()'))
+        g = da.splitGeometryAtAntimeridian(QgsGeometry.fromWkt('LineString EMPTY'))
         self.assertEqual(g.asWkt(), 'MultiLineString EMPTY')
 
         # lines
diff --git a/tests/src/python/test_qgsgeometry.py b/tests/src/python/test_qgsgeometry.py
index 5a2e8558a57b..0781377d2704 100644
--- a/tests/src/python/test_qgsgeometry.py
+++ b/tests/src/python/test_qgsgeometry.py
@@ -842,7 +842,7 @@ def testReferenceGeometry(self):
                                        "Perimeter {}: mismatch Expected:\n{}\nGot:\n{}\n".format(i + 1, exp, result))
 
     def testCollection(self):
-        g = QgsGeometry.fromWkt('MultiLineString()')
+        g = QgsGeometry.fromWkt('MultiLineString EMPTY')
         self.assertEqual(len(g.get()), 0)
         self.assertTrue(g.get())
         g = QgsGeometry.fromWkt('MultiLineString((0 0, 1 1),(13 2, 14 1))')
@@ -4244,42 +4244,42 @@ def testGeometryDisplayString(self):
 
     def testDeleteVertexCircularString(self):
 
-        wkt = "CircularString ((0 0,1 1,2 0))"
+        wkt = "CircularString (0 0,1 1,2 0)"
         geom = QgsGeometry.fromWkt(wkt)
         assert geom.deleteVertex(0)
         self.assertEqual(geom.asWkt(), QgsCircularString().asWkt())
 
-        wkt = "CircularString ((0 0,1 1,2 0,3 -1,4 0))"
+        wkt = "CircularString (0 0,1 1,2 0,3 -1,4 0)"
         geom = QgsGeometry.fromWkt(wkt)
         assert geom.deleteVertex(0)
         expected_wkt = "CircularString (2 0, 3 -1, 4 0)"
         self.assertEqual(geom.asWkt(), QgsGeometry.fromWkt(expected_wkt).asWkt())
 
-        wkt = "CircularString ((0 0,1 1,2 0,3 -1,4 0))"
+        wkt = "CircularString (0 0,1 1,2 0,3 -1,4 0)"
         geom = QgsGeometry.fromWkt(wkt)
         assert geom.deleteVertex(1)
         expected_wkt = "CircularString (0 0, 3 -1, 4 0)"
         self.assertEqual(geom.asWkt(), QgsGeometry.fromWkt(expected_wkt).asWkt())
 
-        wkt = "CircularString ((0 0,1 1,2 0,3 -1,4 0))"
+        wkt = "CircularString (0 0,1 1,2 0,3 -1,4 0)"
         geom = QgsGeometry.fromWkt(wkt)
         assert geom.deleteVertex(2)
         expected_wkt = "CircularString (0 0, 1 1, 4 0)"
         self.assertEqual(geom.asWkt(), QgsGeometry.fromWkt(expected_wkt).asWkt())
 
-        wkt = "CircularString ((0 0,1 1,2 0,3 -1,4 0))"
+        wkt = "CircularString (0 0,1 1,2 0,3 -1,4 0)"
         geom = QgsGeometry.fromWkt(wkt)
         assert geom.deleteVertex(3)
         expected_wkt = "CircularString (0 0, 1 1, 4 0)"
         self.assertEqual(geom.asWkt(), QgsGeometry.fromWkt(expected_wkt).asWkt())
 
-        wkt = "CircularString ((0 0,1 1,2 0,3 -1,4 0))"
+        wkt = "CircularString (0 0,1 1,2 0,3 -1,4 0)"
         geom = QgsGeometry.fromWkt(wkt)
         assert geom.deleteVertex(4)
         expected_wkt = "CircularString (0 0,1 1,2 0)"
         self.assertEqual(geom.asWkt(), QgsGeometry.fromWkt(expected_wkt).asWkt())
 
-        wkt = "CircularString ((0 0,1 1,2 0,3 -1,4 0))"
+        wkt = "CircularString (0 0,1 1,2 0,3 -1,4 0)"
         geom = QgsGeometry.fromWkt(wkt)
         assert not geom.deleteVertex(-1)
         assert not geom.deleteVertex(5)
@@ -4528,7 +4528,7 @@ def testCurveSinuosity(self):
         """
         Test curve straightDistance2d() and sinuosity()
         """
-        linestring = QgsGeometry.fromWkt('LineString()')
+        linestring = QgsGeometry.fromWkt('LineString EMPTY')
         self.assertTrue(math.isnan(linestring.constGet().straightDistance2d()))
         self.assertTrue(math.isnan(linestring.constGet().sinuosity()))
         linestring = QgsGeometry.fromWkt('LineString(0 0, 10 0)')
@@ -4844,7 +4844,7 @@ def testPolygonize(self):
         empty = QgsGeometry()
         o = QgsGeometry.polygonize([empty])
         self.assertFalse(o)
-        line = QgsGeometry.fromWkt('LineString()')
+        line = QgsGeometry.fromWkt('LineString EMPTY')
         o = QgsGeometry.polygonize([line])
         self.assertFalse(o)
 
@@ -4873,7 +4873,7 @@ def testDelaunayTriangulation(self):
         empty = QgsGeometry()
         o = empty.delaunayTriangulation()
         self.assertFalse(o)
-        line = QgsGeometry.fromWkt('LineString()')
+        line = QgsGeometry.fromWkt('LineString EMPTY')
         o = line.delaunayTriangulation()
         self.assertFalse(o)
 
@@ -4952,7 +4952,7 @@ def testVoronoi(self):
         empty = QgsGeometry()
         o = empty.voronoiDiagram()
         self.assertFalse(o)
-        line = QgsGeometry.fromWkt('LineString()')
+        line = QgsGeometry.fromWkt('LineString EMPTY')
         o = line.voronoiDiagram()
         self.assertFalse(o)
 
@@ -5195,7 +5195,7 @@ def testCentroid(self):
                  ["LINESTRING (10 10, 10 10)", "POINT (10 10)"],  # zero length line
                  ["MULTILINESTRING ((10 10, 10 10), (20 20, 20 20))", "POINT (15 15)"],  # zero length multiline
                  ["LINESTRING (60 180, 120 100, 180 180)", "POINT (120 140)"],
-                 ["LINESTRING (80 0, 80 120, 120 120, 120 0))", "POINT (100 68.57142857142857)"],
+                 ["LINESTRING (80 0, 80 120, 120 120, 120 0)", "POINT (100 68.57142857142857)"],
                  ["MULTILINESTRING ((0 0, 0 100), (100 0, 100 100))", "POINT (50 50)"],
                  [" MULTILINESTRING ((0 0, 0 200, 200 200, 200 0, 0 0),(60 180, 20 180, 20 140, 60 140, 60 180))",
                   "POINT (90 110)"],
@@ -5786,24 +5786,24 @@ def coerce_to_wkt(wkt, type):
             coerce_to_wkt('MultiPolygon(((1 1, 2 2, 3 3, 1 1)), ((1 1, 2 2, 3 3, 1 1)))', QgsWkbTypes.MultiPolygon),
             ['MultiPolygon (((1 1, 2 2, 3 3, 1 1)),((1 1, 2 2, 3 3, 1 1)))'])
 
-        self.assertEqual(coerce_to_wkt('LineString((1 1, 2 2, 3 3, 1 1))', QgsWkbTypes.LineString),
-                         ['LineString (0 1, 2 2, 3 3, 1 0)'])
-        self.assertEqual(coerce_to_wkt('LineString z ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', QgsWkbTypes.LineString),
-                         ['LineString (0 1, 2 2, 3 3, 1 1)'])
-        self.assertEqual(coerce_to_wkt('LineString z ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', QgsWkbTypes.LineStringZ),
-                         ['LineStringZ (0 1 1, 2 2 2, 3 3 3, 1 1 0)'])
-        self.assertEqual(coerce_to_wkt('LineString m ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', QgsWkbTypes.LineString),
-                         ['LineString (0 1, 2 2, 3 3, 1 1)'])
-        self.assertEqual(coerce_to_wkt('LineString m ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', QgsWkbTypes.LineStringM),
-                         ['LineStringM (0 1 1, 2 2 2, 3 3 3, 1 1 0)'])
+        self.assertEqual(coerce_to_wkt('LineString(1 1, 2 2, 3 3, 1 1)', QgsWkbTypes.LineString),
+                         ['LineString (1 1, 2 2, 3 3, 1 1)'])
+        self.assertEqual(coerce_to_wkt('LineString z (1 1 1, 2 2 2, 3 3 3, 1 1 1)', QgsWkbTypes.LineString),
+                         ['LineString (1 1, 2 2, 3 3, 1 1)'])
+        self.assertEqual(coerce_to_wkt('LineString z (1 1 1, 2 2 2, 3 3 3, 1 1 1)', QgsWkbTypes.LineStringZ),
+                         ['LineStringZ (1 1 1, 2 2 2, 3 3 3, 1 1 1)'])
+        self.assertEqual(coerce_to_wkt('LineString m (1 1 1, 2 2 2, 3 3 3, 1 1 1)', QgsWkbTypes.LineString),
+                         ['LineString (1 1, 2 2, 3 3, 1 1)'])
+        self.assertEqual(coerce_to_wkt('LineString m (1 1 1, 2 2 2, 3 3 3, 1 1 1)', QgsWkbTypes.LineStringM),
+                         ['LineStringM (1 1 1, 2 2 2, 3 3 3, 1 1 1)'])
 
         # Adding Z back
-        self.assertEqual(coerce_to_wkt('LineString (1 1, 2 2, 3 3, 1 1))', QgsWkbTypes.LineStringZ),
-                         ['LineStringZ (1 1 0, 2 2 0, 3 3 0, 1 0 0)'])
+        self.assertEqual(coerce_to_wkt('LineString (1 1, 2 2, 3 3, 1 1)', QgsWkbTypes.LineStringZ),
+                         ['LineStringZ (1 1 0, 2 2 0, 3 3 0, 1 1 0)'])
 
         # Adding M back
-        self.assertEqual(coerce_to_wkt('LineString (1 1, 2 2, 3 3, 1 1))', QgsWkbTypes.LineStringM),
-                         ['LineStringM (1 1 0, 2 2 0, 3 3 0, 1 0 0)'])
+        self.assertEqual(coerce_to_wkt('LineString (1 1, 2 2, 3 3, 1 1)', QgsWkbTypes.LineStringM),
+                         ['LineStringM (1 1 0, 2 2 0, 3 3 0, 1 1 0)'])
 
         self.assertEqual(coerce_to_wkt('LineString(1 1, 2 2, 3 3, 1 1)', QgsWkbTypes.MultiLineString),
                          ['MultiLineString ((1 1, 2 2, 3 3, 1 1))'])
diff --git a/tests/src/python/test_qgsprocessinginplace.py b/tests/src/python/test_qgsprocessinginplace.py
index cfcb7031ea75..fdb2002cf0cb 100644
--- a/tests/src/python/test_qgsprocessinginplace.py
+++ b/tests/src/python/test_qgsprocessinginplace.py
@@ -250,7 +250,7 @@ def test_QgsVectorLayerUtilsmakeFeaturesCompatible(self):
         self._make_compatible_tester('MultiPoint((1 3), (2 2))', 'MultiPoint')
 
         self._make_compatible_tester('Polygon((1 1, 2 2, 3 3, 1 1))', 'Polygon')
-        self._make_compatible_tester('Polygon((1 1, 2 2, 3 3, 1 1)', 'Polygon', [1, 'nope'])
+        self._make_compatible_tester('Polygon((1 1, 2 2, 3 3, 1 1))', 'Polygon', [1, 'nope'])
         self._make_compatible_tester('Polygon z ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', 'Polygon')
         self._make_compatible_tester('Polygon z ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', 'PolygonZ')
 
@@ -273,22 +273,22 @@ def test_QgsVectorLayerUtilsmakeFeaturesCompatible(self):
         self._make_compatible_tester('Polygon((1 1, 2 2, 3 3, 1 1))', 'MultiPolygon')
         self._make_compatible_tester('MultiPolygon(((1 1, 2 2, 3 3, 1 1)), ((1 1, 2 2, 3 3, 1 1)))', 'MultiPolygon')
 
-        self._make_compatible_tester('LineString((1 1, 2 2, 3 3, 1 1))', 'LineString')
-        self._make_compatible_tester('LineString((1 1, 2 2, 3 3, 1 1)', 'LineString', [1, 'nope'])
-        self._make_compatible_tester('LineString z ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', 'LineString')
-        self._make_compatible_tester('LineString z ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', 'LineStringZ')
-        self._make_compatible_tester('LineString m ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', 'LineString')
-        self._make_compatible_tester('LineString m ((1 1 1, 2 2 2, 3 3 3, 1 1 1))', 'LineStringM')
+        self._make_compatible_tester('LineString(1 1, 2 2, 3 3, 1 1)', 'LineString')
+        self._make_compatible_tester('LineString(1 1, 2 2, 3 3, 1 1)', 'LineString', [1, 'nope'])
+        self._make_compatible_tester('LineString z (1 1 1, 2 2 2, 3 3 3, 1 1 1)', 'LineString')
+        self._make_compatible_tester('LineString z (1 1 1, 2 2 2, 3 3 3, 1 1 1)', 'LineStringZ')
+        self._make_compatible_tester('LineString m (1 1 1, 2 2 2, 3 3 3, 1 1 1)', 'LineString')
+        self._make_compatible_tester('LineString m (1 1 1, 2 2 2, 3 3 3, 1 1 1)', 'LineStringM')
 
         # Adding Z back
-        l, f = self._make_compatible_tester('LineString (1 1, 2 2, 3 3, 1 1))', 'LineStringZ')
+        l, f = self._make_compatible_tester('LineString (1 1, 2 2, 3 3, 1 1)', 'LineStringZ')
         g = f[0].geometry()
         g2 = g.constGet()
         for v in g2.vertices():
             self.assertEqual(v.z(), 0)
 
         # Adding M back
-        l, f = self._make_compatible_tester('LineString (1 1, 2 2, 3 3, 1 1))', 'LineStringM')
+        l, f = self._make_compatible_tester('LineString (1 1, 2 2, 3 3, 1 1)', 'LineStringM')
         g = f[0].geometry()
         g2 = g.constGet()
         for v in g2.vertices():
diff --git a/tests/testdata/relates_data.csv b/tests/testdata/relates_data.csv
index 9b9ef08d1ee3..70bbb05276a9 100644
--- a/tests/testdata/relates_data.csv
+++ b/tests/testdata/relates_data.csv
@@ -47,7 +47,7 @@ LINESTRING(20 20,100 20,20 20)|LINESTRING(60 20,200 20)|101FFF102
 LINESTRING(40 60,180 60,180 140,100 140,100 60,220 60,220 180,80 180,80 60,280 60)|LINESTRING(140 60,180 60,220 60,260 60)|101FF0FF2
 POINT(20 20)|POLYGON((60 120,60 40,160 40,160 120,60 120))|FF0FFF212
 MULTIPOINT(0 20,40 20)|POLYGON((20 40,20 0,60 0,60 40,20 40))|0F0FFF212
-MULTIPOINT(0 20,20 20))|POLYGON((20 40,20 0,60 0,60 40,20 40))|F00FFF212
+MULTIPOINT(0 20,20 20)|POLYGON((20 40,20 0,60 0,60 40,20 40))|F00FFF212
 MULTIPOINT(20 20,40 20)|POLYGON((20 40,20 0,60 0,60 40,20 40))|00FFFF212
 MULTIPOINT(80 260,140 260,180 260)|POLYGON((40 320,140 320,140 200,40 200,40 320))|000FFF212
 POINT(40 40)|MULTIPOLYGON(((0 40,0 0,40 0,40 40,0 40)),((40 80,40 40,80 40,80 80,40 80)))|F0FFFF212