test_read_basis in test_highspy.py needs initial column basis status to be HighsBasisStatus.kNonbasic

Author: jajhall

check/TestBasis.cpp

@@ -315,3 +315,43 @@ void testBasisRestart(Highs& highs, const std::string& basis_file,
 
   REQUIRE(info.simplex_iteration_count == 0);
 }
+
+TEST_CASE("Basis-read", "[highs_basis_data]") {
+  // Duplicates test_read_basis in test_highspy.py
+  const std::string test_name = Catch::getResultCapture().getCurrentTestName();
+
+  HighsLp lp;
+  lp.num_col_ = 2;
+  lp.num_row_ = 2;
+  lp.col_cost_ = {0, 1};
+  lp.col_lower_.assign(lp.num_col_, -kHighsInf);
+  lp.col_upper_.assign(lp.num_col_, kHighsInf);
+  lp.row_lower_ = {2, 0};
+  lp.row_upper_.assign(lp.num_row_, kHighsInf);
+  lp.a_matrix_.start_ = {0, 2, 4};
+  lp.a_matrix_.index_ = {0, 1, 0, 1};
+  lp.a_matrix_.value_ = {-1, 1, 1, 1};
+
+  HighsBasisStatus status_before = HighsBasisStatus::kNonbasic;
+  HighsBasisStatus status_after = HighsBasisStatus::kBasic;
+  Highs h1;
+  const HighsBasis& basis1 = h1.getBasis();
+  h1.passModel(lp);
+  REQUIRE(basis1.col_status[0] == status_before);
+  h1.run();
+  REQUIRE(basis1.col_status[0] == status_after);
+
+  Highs h2;
+  const HighsBasis& basis2 = h2.getBasis();
+  h2.passModel(lp);
+  REQUIRE(basis2.col_status[0] == status_before);
+
+  const std::string basis_file = test_name + ".bas";
+  h1.writeBasis(basis_file);
+  h2.readBasis(basis_file);
+  REQUIRE(basis2.col_status[0] == status_after);
+
+  std::remove(basis_file.c_str());
+  h1.resetGlobalScheduler(true);
+  h2.resetGlobalScheduler(true);
+}

tests/test_highspy.py

@@ -1004,7 +1004,7 @@ def test_write_basis_after_running(self):
     def test_read_basis(self):
         if platform == "linux" or platform == "darwin":
             # Read basis from one run model into an unrun model
-            expected_status_before = highspy.HighsBasisStatus.kLower
+            expected_status_before = highspy.HighsBasisStatus.kNonbasic
             expected_status_after = highspy.HighsBasisStatus.kBasic
 
             h1 = self.get_basic_model()