Improve test coverage

src/constraints.jl

@@ -465,11 +465,10 @@ function constraint_by_name end
 
 function constraint_by_name(model::GenericModel, name::String)
     index = MOI.get(backend(model), MOI.ConstraintIndex, name)
-    if index isa Nothing
+    if index === nothing
         return nothing
-    else
-        return constraint_ref_with_index(model, index)
     end
+    return constraint_ref_with_index(model, index)
 end
 
 function constraint_by_name(
@@ -479,7 +478,7 @@ function constraint_by_name(
     ::Type{S},
 ) where {F<:MOI.AbstractFunction,S<:MOI.AbstractSet}
     index = MOI.get(backend(model), MOI.ConstraintIndex{F,S}, name)
-    if index isa Nothing
+    if index === nothing
         return nothing
     end
     return constraint_ref_with_index(model, index)

src/nlp_expr.jl

@@ -632,15 +632,13 @@ function jump_function(model::GenericModel, expr::MOI.Nonlinear.Expression)
             )
         elseif node.type == MOI.Nonlinear.NODE_MOI_VARIABLE
             V(model, MOI.VariableIndex(node.index))
-        elseif node.type == MOI.Nonlinear.NODE_PARAMETER
-            NonlinearParameter(model, node.index)
-        elseif node.type == MOI.Nonlinear.NODE_SUBEXPRESSION
-            NonlinearExpression(model, node.index)
         elseif node.type == MOI.Nonlinear.NODE_VALUE
             expr.values[node.index]
         else
             # node.type == MOI.Nonlinear.NODE_COMPARISON
             # node.type == MOI.Nonlinear.NODE_LOGIC
+            # node.type == MOI.Nonlinear.NODE_PARAMETER
+            # node.type == MOI.Nonlinear.NODE_SUBEXPRESSION
             error("Unsupported node")
         end
     end

src/operators.jl

@@ -445,10 +445,15 @@ Base.transpose(x::AbstractJuMPScalar) = x
 Base.conj(x::GenericVariableRef) = x
 # Can remove the following code once == overloading is removed
 
-function LinearAlgebra.issymmetric(x::Matrix{T}) where {T<:_JuMPTypes}
-    (n = size(x, 1)) == size(x, 2) || return false
+function LinearAlgebra.issymmetric(x::Matrix{<:_JuMPTypes})
+    n = size(x, 1)
+    if n != size(x, 2)
+        return false
+    end
     for i in 1:n, j in (i+1):n
-        isequal(x[i, j], x[j, i]) || return false
+        if !isequal(x[i, j], x[j, i])
+            return false
+        end
     end
     return true
 end

test/test_constraint.jl

@@ -621,7 +621,7 @@ function _test_constraint_name_util(ModelType, VariableRefType)
         MOI.EqualTo{Float64},
     )
     set_name(con, "kon")
-    @test constraint_by_name(model, "con") isa Nothing
+    @test constraint_by_name(model, "con") === nothing
     _test_constraint_name_util(
         con,
         "kon",
@@ -646,7 +646,7 @@ function _test_constraint_name_util(ModelType, VariableRefType)
     )
     set_name(con, "con")
     @test_throws err("con") constraint_by_name(model, "con")
-    @test constraint_by_name(model, "kon") isa Nothing
+    @test constraint_by_name(model, "kon") === nothing
     set_name(kon, "kon")
     _test_constraint_name_util(
         con,
@@ -2157,4 +2157,18 @@ function test_hermitian_shape()
     return
 end
 
+function test_constraint_by_name()
+    model = Model()
+    @variable(model, x)
+    @constraint(model, c, 2x <= 1)
+    @test constraint_by_name(model, "c") === c
+    @test constraint_by_name(model, "d") === nothing
+    F, S1, S2 = AffExpr, MOI.LessThan{Float64}, MOI.GreaterThan{Float64}
+    @test constraint_by_name(model, "c", F, S1) === c
+    @test constraint_by_name(model, "c", F, S2) === nothing
+    @test constraint_by_name(model, "d", F, S1) === nothing
+    @test constraint_by_name(model, "d", F, S2) === nothing
+    return
+end
+
 end  # module

test/test_model.jl

@@ -984,6 +984,7 @@ function test_optimize_not_called_warning()
     end
     @variable(model, x >= 0)
     @constraint(model, c, 2x <= 1)
+    @test_throws OptimizeNotCalled value(x)
     optimize!(model)
     set_start_value(x, 0.0)
     @test_logs (:warn,) (@test_throws OptimizeNotCalled objective_value(model))
@@ -1348,4 +1349,19 @@ function test_iterate_scalar()
     return
 end
 
+function test_optimizer_index()
+    model = Model() do
+        inner = MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}())
+        return MOI.Utilities.MockOptimizer(inner)
+    end
+    @variable(model, x)
+    @test_throws(
+        ErrorException(
+            "There is no `optimizer_index` as the optimizer is not synchronized with the cached model. Call `MOIU.attach_optimizer(model)` to synchronize it.",
+        ),
+        optimizer_index(x),
+    )
+    return
+end
+
 end  # module TestModels

test/test_nlp_expr.jl

@@ -1122,4 +1122,16 @@ function test_error_legacy_parameter_constructor()
     return
 end
 
+function test_promote_type()
+    F = GenericNonlinearExpr{GenericVariableRef{Int}}
+    G = GenericNonlinearExpr{GenericVariableRef{Float64}}
+    @test_throws(
+        ErrorException(
+            "Unable to promote two different types of nonlinear expression",
+        ),
+        MA.promote_operation(+, F, G),
+    )
+    return
+end
+
 end  # module

test/test_operator.jl

@@ -264,11 +264,21 @@ function test_extension_operator_warn(
     if ModelType <: Model
         @test model.operator_counter == 0
     end
-    # Triggers the increment of operator_counter since sum(x) has more than 50 terms
-    @test_expression(sum(x) + 2x[1])
-    if ModelType <: Model
-        # The following check verifies that this test covers the code incrementing `operator_counter`
-        @test model.operator_counter == 1
+    lhs = sum(x)
+    rhs = 2 * x[1]
+    for i in 1:20_001
+        # Triggers the increment of operator_counter since lhs has more than
+        # 50 terms
+        if i == 20_001 && ModelType <: Model
+            @test_logs (:warn,) lhs + rhs
+        else
+            lhs + rhs
+        end
+        if ModelType <: Model
+            # The following check verifies that this test covers the code
+            # incrementing `operator_counter`
+            @test model.operator_counter == i
+        end
     end
     return
 end
@@ -723,4 +733,13 @@ function test_hermitian_and_symmetric()
     return
 end
 
+function test_is_symmetric()
+    model = Model()
+    @variable(model, x[1:3])
+    @test !LinearAlgebra.issymmetric([x[1] x[2]; x[3] x[3]])
+    @test !LinearAlgebra.issymmetric([x[1] x[2]])
+    @test LinearAlgebra.issymmetric([x[1] x[2]; x[2] x[3]])
+    return
+end
+
 end

test/test_variable.jl

@@ -376,7 +376,7 @@ function test_extension_variable_name(
     @variable(model, x)
     _test_variable_name_util(x, "x")
     set_name(x, "y")
-    @test variable_by_name(model, "x") isa Nothing
+    @test variable_by_name(model, "x") === nothing
     _test_variable_name_util(x, "y")
     y = @variable(model, base_name = "y")
     err(name) = ErrorException("Multiple variables have the name $name.")
@@ -386,7 +386,7 @@ function test_extension_variable_name(
     _test_variable_name_util(y, "x")
     set_name(x, "x")
     @test_throws err("x") variable_by_name(model, "x")
-    @test variable_by_name(model, "y") isa Nothing
+    @test variable_by_name(model, "y") === nothing
     set_name(y, "y")
     _test_variable_name_util(x, "x")
     _test_variable_name_util(y, "y")