Improve coverage of constraints.jl

src/constraints.jl

@@ -274,14 +274,9 @@ function Base.showerror(io::IO, err::LowerBoundAlreadySet{S1,S2}) where {S1,S2}
     return print(
         io,
         typeof(err),
-        ": Cannot add `SingleVariable`-in`",
-        S2,
-        "` constraint for variable ",
-        err.vi,
-        " as a `SingleVariable`-in`",
-        S1,
-        "` constraint was already set for this variable and both",
-        " constraints set a lower bound.",
+        ": Cannot add `SingleVariable`-in-`$(S2)` constraint for variable ",
+        "$(err.vi) as a `SingleVariable`-in-`$(S1)` constraint was already ",
+        "set for this variable and both constraints set a lower bound.",
     )
 end
 
@@ -301,14 +296,9 @@ function Base.showerror(io::IO, err::UpperBoundAlreadySet{S1,S2}) where {S1,S2}
     return print(
         io,
         typeof(err),
-        ": Cannot add `SingleVariable`-in`",
-        S2,
-        "` constraint for variable ",
-        err.vi,
-        " as a `SingleVariable`-in`",
-        S1,
-        "` constraint was already set for this variable and both",
-        " constraints set an upper bound.",
+        ": Cannot add `SingleVariable`-in-`$(S2)` constraint for variable ",
+        "$(err.vi) as a `SingleVariable`-in-`$(S1)` constraint was already ",
+        "set for this variable and both constraints set an upper bound.",
     )
 end
 

test/constraints.jl

@@ -1,9 +1,20 @@
 module TestConstraints
 
 using Test
+
 using MathOptInterface
 const MOI = MathOptInterface
 
+function runtests()
+    for name in names(@__MODULE__; all = true)
+        if startswith("$name", "test_")
+            @testset "$(name)" begin
+                getfield(@__MODULE__, name)()
+            end
+        end
+    end
+end
+
 function _constant_not_zero_test(::Type{T}) where {T}
     S = MOI.EqualTo{T}
     x = MOI.VariableIndex(1)
@@ -25,14 +36,42 @@ function test_constraints_ConstantNotZero()
     return
 end
 
-function runtests()
-    for name in names(@__MODULE__; all = true)
-        if startswith("$name", "test_")
-            @testset "$(name)" begin
-                getfield(@__MODULE__, name)()
-            end
-        end
-    end
+function test_LowerBoundAlreadySet_error()
+    x = MOI.VariableIndex(1)
+    S1 = MOI.LessThan{Int}
+    S2 = MOI.Interval{Int}
+    err = MOI.LowerBoundAlreadySet{S1,S2}(x)
+    @test sprint(showerror, err) ==
+          "$(typeof(err)): Cannot add `SingleVariable`-in-`$(S2)` constraint " *
+          "for variable $(x) as a `SingleVariable`-in-`$(S1)` constraint was " *
+          "already set for this variable and both constraints set a lower bound."
+    return
+end
+
+function test_UpperBoundAlreadySet_error()
+    x = MOI.VariableIndex(1)
+    S1 = MOI.GreaterThan{Int}
+    S2 = MOI.Interval{Int}
+    err = MOI.UpperBoundAlreadySet{S1,S2}(x)
+    @test sprint(showerror, err) ==
+          "$(typeof(err)): Cannot add `SingleVariable`-in-`$(S2)` constraint " *
+          "for variable $(x) as a `SingleVariable`-in-`$(S1)` constraint was " *
+          "already set for this variable and both constraints set an upper bound."
+    return
+end
+
+function test_ScalarFunctionConstantNotZero_error()
+    x = MOI.VariableIndex(1)
+    T = Int
+    F = MOI.ScalarAffineFunction{T}
+    S = MOI.EqualTo{T}
+    err = MOI.ScalarFunctionConstantNotZero{T,F,S}(one(T))
+    @test sprint(showerror, err) ==
+          "In `$F`-in-`$S` constraint: Constant $(one(T)) of the function is " *
+          "not zero. The function constant should be moved to the set. You can " *
+          "use `MOI.Utilities.normalize_and_add_constraint` which does this " *
+          "automatically."
+    return
 end
 
 end