--- /dev/null
+## Copyright (C) 2018-20xx CEA/DEN, EDF R&D
+##
+## This library is free software; you can redistribute it and/or
+## modify it under the terms of the GNU Lesser General Public
+## License as published by the Free Software Foundation; either
+## version 2.1 of the License, or (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public
+## License along with this library; if not, write to the Free Software
+## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##
+## See http:##www.salome-platform.org/ or
+## email : webmaster.salome@opencascade.com<mailto:webmaster.salome@opencascade.com>
+##
+
+"""
+ Test1577.py
+ Test case for issue #1577 "distance constraint change sign"
+"""
+
+from salome.shaper import model
+import math
+
+model.begin()
+partSet = model.moduleDocument()
+Part_1 = model.addPart(partSet)
+Part_1_doc = Part_1.document()
+model.addParameter(Part_1_doc, "Base_Off", "5.875")
+model.addParameter(Part_1_doc, "Base_H", "3")
+model.addParameter(Part_1_doc, "Base_B", "1.5")
+model.addParameter(Part_1_doc, "Wall_R", "6.188")
+model.addParameter(Part_1_doc, "Wall_T1", "0.089")
+model.addParameter(Part_1_doc, "Wall_T2", "0.261")
+model.addParameter(Part_1_doc, "Wall_H", "12.465")
+model.addParameter(Part_1_doc, "StrGal_B", "0.75")
+model.addParameter(Part_1_doc, "StrGal_H", "1.8")
+model.addParameter(Part_1_doc, "StrGal_BU", "0.6")
+model.addParameter(Part_1_doc, "StrGal_Inc", "0.2")
+model.addParameter(Part_1_doc, "Bracket_H", "1.2")
+model.addParameter(Part_1_doc, "Bracket_B", "0.15")
+model.addParameter(Part_1_doc, "Bracket_B1", "0.256")
+model.addParameter(Part_1_doc, "Bracket_B2", "0.094")
+model.addParameter(Part_1_doc, "Bracket_H1", "1.226")
+model.addParameter(Part_1_doc, "Cover_R", "9.794")
+model.addParameter(Part_1_doc, "Cover_T", "0.082")
+model.addParameter(Part_1_doc, "Cover_T1", "0.125")
+Sketch_1 = model.addSketch(Part_1_doc, model.defaultPlane("XOY"))
+SketchPoint_1 = Sketch_1.addPoint(0, 2.425)
+SketchConstraintRigid_1 = Sketch_1.setFixed(SketchPoint_1.coordinates())
+SketchLine_1 = Sketch_1.addLine(6.277, 12.18846022232796, 6.277, -8.121250994790044)
+SketchLine_1.setAuxiliary(True)
+SketchConstraintVertical_1 = Sketch_1.setVertical(SketchLine_1.result())
+SketchConstraintDistance_1 = Sketch_1.setDistance(SketchPoint_1.coordinates(), SketchLine_1.result(), "Wall_R+Wall_T1", False)
+SketchLine_2 = Sketch_1.addLine(6.538, -3.45, 7.777, -3.45)
+SketchLine_3 = Sketch_1.addLine(7.777, -3.45, 7.777, -6.45)
+SketchConstraintCoincidence_1 = Sketch_1.setCoincident(SketchLine_2.endPoint(), SketchLine_3.startPoint())
+SketchLine_4 = Sketch_1.addLine(7.777, -6.45, 0, -6.45)
+SketchConstraintCoincidence_2 = Sketch_1.setCoincident(SketchLine_3.endPoint(), SketchLine_4.startPoint())
+SketchLine_5 = Sketch_1.addLine(0, -6.45, 0, -3.45)
+SketchConstraintCoincidence_3 = Sketch_1.setCoincident(SketchLine_4.endPoint(), SketchLine_5.startPoint())
+SketchLine_6 = Sketch_1.addLine(0, -3.45, 6.188, -3.45)
+SketchConstraintCoincidence_4 = Sketch_1.setCoincident(SketchLine_5.endPoint(), SketchLine_6.startPoint())
+SketchConstraintVertical_2 = Sketch_1.setVertical(SketchLine_3.result())
+SketchConstraintVertical_3 = Sketch_1.setVertical(SketchLine_5.result())
+SketchConstraintHorizontal_1 = Sketch_1.setHorizontal(SketchLine_6.result())
+SketchConstraintHorizontal_2 = Sketch_1.setHorizontal(SketchLine_2.result())
+SketchConstraintHorizontal_3 = Sketch_1.setHorizontal(SketchLine_4.result())
+SketchConstraintDistance_2 = Sketch_1.setDistance(SketchPoint_1.coordinates(), SketchLine_6.result(), "Base_Off", False)
+SketchConstraintDistance_3 = Sketch_1.setDistance(SketchPoint_1.coordinates(), SketchLine_2.result(), "Base_Off", False)
+SketchConstraintDistance_4 = Sketch_1.setDistance(SketchLine_2.endPoint(), SketchLine_4.result(), "Base_H", False)
+SketchConstraintDistance_5 = Sketch_1.setDistance(SketchLine_4.startPoint(), SketchLine_1.result(), "Base_B", False)
+SketchConstraintDistance_6 = Sketch_1.setDistance(SketchLine_5.startPoint(), SketchLine_1.result(), "Wall_R+Wall_T1", False)
+SketchConstraintDistance_7 = Sketch_1.setDistance(SketchLine_6.endPoint(), SketchLine_1.result(), "Wall_T1", False)
+SketchConstraintDistance_8 = Sketch_1.setDistance(SketchLine_1.result(), SketchLine_2.startPoint(), "Wall_T2", False)
+SketchLine_7 = Sketch_1.addLine(5.677, -4.05, 6.877, -4.05)
+SketchLine_8 = Sketch_1.addLine(6.877, -4.05, 7.027, -4.25)
+SketchConstraintCoincidence_5 = Sketch_1.setCoincident(SketchLine_7.endPoint(), SketchLine_8.startPoint())
+SketchLine_9 = Sketch_1.addLine(7.027, -4.25, 7.027, -5.85)
+SketchConstraintCoincidence_6 = Sketch_1.setCoincident(SketchLine_8.endPoint(), SketchLine_9.startPoint())
+SketchLine_10 = Sketch_1.addLine(7.027, -5.85, 5.527, -5.85)
+SketchConstraintCoincidence_7 = Sketch_1.setCoincident(SketchLine_9.endPoint(), SketchLine_10.startPoint())
+SketchLine_11 = Sketch_1.addLine(5.527, -5.85, 5.527, -4.25)
+SketchConstraintCoincidence_8 = Sketch_1.setCoincident(SketchLine_10.endPoint(), SketchLine_11.startPoint())
+SketchLine_12 = Sketch_1.addLine(5.527, -4.25, 5.677, -4.05)
+SketchConstraintCoincidence_9 = Sketch_1.setCoincident(SketchLine_11.endPoint(), SketchLine_12.startPoint())
+SketchConstraintCoincidence_10 = Sketch_1.setCoincident(SketchLine_7.startPoint(), SketchLine_12.endPoint())
+SketchConstraintVertical_4 = Sketch_1.setVertical(SketchLine_9.result())
+SketchConstraintVertical_5 = Sketch_1.setVertical(SketchLine_11.result())
+SketchConstraintHorizontal_4 = Sketch_1.setHorizontal(SketchLine_7.result())
+SketchConstraintHorizontal_5 = Sketch_1.setHorizontal(SketchLine_10.result())
+SketchConstraintDistance_9 = Sketch_1.setDistance(SketchLine_10.endPoint(), SketchLine_1.result(), "StrGal_B", False)
+SketchConstraintDistance_10 = Sketch_1.setDistance(SketchLine_10.startPoint(), SketchLine_1.result(), "StrGal_B", False)
+SketchConstraintDistance_11 = Sketch_1.setDistance(SketchLine_12.endPoint(), SketchLine_1.result(), "StrGal_BU", False)
+SketchConstraintDistance_12 = Sketch_1.setDistance(SketchLine_7.endPoint(), SketchLine_1.result(), "StrGal_BU", False)
+SketchConstraintDistance_13 = Sketch_1.setDistance(SketchLine_7.endPoint(), SketchLine_10.result(), "StrGal_H", False)
+SketchConstraintDistance_14 = Sketch_1.setDistance(SketchLine_7.endPoint(), SketchLine_2.result(), 0.6, True)
+SketchConstraintDistance_15 = Sketch_1.setDistance(SketchLine_9.startPoint(), SketchLine_7.result(), "StrGal_Inc", False)
+SketchConstraintDistance_16 = Sketch_1.setDistance(SketchLine_11.endPoint(), SketchLine_7.result(), "StrGal_Inc", False)
+SketchLine_13 = Sketch_1.addLine(6.188, -3.45, 6.188, 0.287301537219)
+SketchConstraintCoincidence_11 = Sketch_1.setCoincident(SketchLine_6.endPoint(), SketchLine_13.startPoint())
+SketchLine_14 = Sketch_1.addLine(6.538, -3.45, 6.538, -1.380737101082)
+SketchConstraintCoincidence_12 = Sketch_1.setCoincident(SketchLine_2.startPoint(), SketchLine_14.startPoint())
+SketchLine_15 = Sketch_1.addLine(6.538, -1.380737101082, 6.366, -1.102730661365)
+SketchConstraintCoincidence_13 = Sketch_1.setCoincident(SketchLine_14.endPoint(), SketchLine_15.startPoint())
+SketchLine_16 = Sketch_1.addLine(6.366, -1.102730661365, 6.366, 0.21779992729)
+SketchConstraintCoincidence_14 = Sketch_1.setCoincident(SketchLine_15.endPoint(), SketchLine_16.startPoint())
+SketchConstraintVertical_6 = Sketch_1.setVertical(SketchLine_13.result())
+SketchConstraintVertical_7 = Sketch_1.setVertical(SketchLine_14.result())
+SketchConstraintVertical_8 = Sketch_1.setVertical(SketchLine_16.result())
+SketchConstraintDistance_17 = Sketch_1.setDistance(SketchLine_16.endPoint(), SketchLine_1.result(), "Wall_T1", False)
+model.do()
+
+# store coordinates of the gallery
+Lines = [SketchLine_7, SketchLine_8, SketchLine_9, SketchLine_10, SketchLine_11, SketchLine_12]
+RefCoorindates = []
+for line in Lines:
+ RefCoorindates.append(line.startPoint().x())
+ RefCoorindates.append(line.startPoint().y())
+ RefCoorindates.append(line.endPoint().x())
+ RefCoorindates.append(line.endPoint().y())
+
+SketchConstraintDistance_18 = Sketch_1.setDistance(SketchLine_14.endPoint(), SketchLine_2.result(), "Wall_H", True)
+model.do()
+
+# check coordinates of lines are not changed
+TOLERANCE = 1e-6
+index = 0
+for line in Lines:
+ assert(math.fabs(line.startPoint().x() - RefCoorindates[index]) < TOLERANCE)
+ assert(math.fabs(line.startPoint().y() - RefCoorindates[index + 1]) < TOLERANCE)
+ assert(math.fabs(line.endPoint().x() - RefCoorindates[index + 2]) < TOLERANCE)
+ assert(math.fabs(line.endPoint().y() - RefCoorindates[index + 3]) < TOLERANCE)
+ index += 4
+
+model.end()
