diff --git a/test/Project.toml b/test/Project.toml
index fdb058f2..34c41bb0 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -1,23 +1,14 @@
 [deps]
-ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
 DelimitedFiles = "8bb1440f-4735-579b-a4ab-409b98df4dab"
-DiffOpt = "930fe3bc-9c6b-11ea-2d94-6184641e85e7"
-Flux = "587475ba-b771-5e3f-ad9e-33799f191a9c"
 HiGHS = "87dc4568-4c63-4d18-b0c0-bb2238e4078b"
-Ipopt = "b6b21f68-93f8-5de0-b562-5493be1d77c9"
 IterativeSolvers = "42fd0dbc-a981-5370-80f2-aaf504508153"
 JuMP = "4076af6c-e467-56ae-b986-b466b2749572"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
-MLDatasets = "eb30cadb-4394-5ae3-aed4-317e484a6458"
 MathOptInterface = "b8f27783-ece8-5eb3-8dc8-9495eed66fee"
-Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
-Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 SCS = "c946c3f1-0d1f-5ce8-9dea-7daa1f7e2d13"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
-Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [compat]
 HiGHS = "1"
-Ipopt = "1.0.2"
 SCS = "1"
diff --git a/test/conic_program.jl b/test/conic_program.jl
index a3d4a939..a3bad7ec 100644
--- a/test/conic_program.jl
+++ b/test/conic_program.jl
@@ -7,7 +7,7 @@ module TestConicProgram
 
 using Test
 import DiffOpt
-import Ipopt
+import HiGHS
 import LinearAlgebra
 import MathOptInterface as MOI
 import SCS
@@ -848,7 +848,7 @@ function test_singular_exception()
     q = [1.0, 1.0]
     G = [1.0 1.0]
     h = [-1.0]
-    model = DiffOpt.diff_optimizer(Ipopt.Optimizer)
+    model = DiffOpt.diff_optimizer(HiGHS.Optimizer)
     MOI.set(model, MOI.Silent(), true)
     x = MOI.add_variables(model, 2)
     quad_terms = MOI.ScalarQuadraticTerm{Float64}[]
diff --git a/test/jump.jl b/test/jump.jl
index cacb27ae..7b071c1e 100644
--- a/test/jump.jl
+++ b/test/jump.jl
@@ -11,7 +11,6 @@ using JuMP
 import DelimitedFiles
 import DiffOpt
 import HiGHS
-import Ipopt
 import IterativeSolvers
 import LinearAlgebra
 import MathOptInterface as MOI
@@ -44,7 +43,7 @@ function test_forward_on_trivial_qp()
         0.0 -1.0
     ]
     h = [1, 0.7, 0.7, -1, 0, 0]
-    model = JuMP.Model(() -> DiffOpt.diff_optimizer(Ipopt.Optimizer))
+    model = JuMP.Model(() -> DiffOpt.diff_optimizer(HiGHS.Optimizer))
     MOI.set(model, MOI.Silent(), true)
     @variable(model, x[1:2])
     @objective(model, Min, x' * Q * x + q' * x)
@@ -59,7 +58,7 @@ function test_differentiating_trivial_qp_1()
     q = [1.0, 1.0]
     G = [1.0 1.0]
     h = [-1.0]
-    model = JuMP.direct_model(DiffOpt.diff_optimizer(Ipopt.Optimizer))
+    model = JuMP.direct_model(DiffOpt.diff_optimizer(HiGHS.Optimizer))
     MOI.set(model, MOI.Silent(), true)
     x = @variable(model, [1:2])
     @objective(model, Min, x' * Q * x + q' * x)
@@ -103,7 +102,7 @@ function test_differentiating_qp_with_inequality_and_equality_constraints()
     h = [1.0, 1.0, 1.0, 0.0, 0.0, 0.0]
     A = [1.0 1.0 1.0;]
     b = [0.5]
-    model = Model(() -> DiffOpt.diff_optimizer(Ipopt.Optimizer))
+    model = Model(() -> DiffOpt.diff_optimizer(HiGHS.Optimizer))
     MOI.set(model, MOI.Silent(), true)
     @variable(model, x[1:3])
     @objective(model, Min, x' * Q * x + q' * x)
@@ -147,7 +146,7 @@ function test_differentiating_MOI_examples_1()
     # st  x + 2y + 3z >= 4 (c1)
     #     x +  y      >= 1 (c2)
     #     x, y, z \in R
-    model = JuMP.direct_model(DiffOpt.diff_optimizer(Ipopt.Optimizer))
+    model = JuMP.direct_model(DiffOpt.diff_optimizer(HiGHS.Optimizer))
     MOI.set(model, MOI.Silent(), true)
     @variables(model, begin
         x
@@ -191,7 +190,7 @@ function test_differentiating_moi_examples_2_non_trivial_backward_pass_vector()
     #    minimize 2 x^2 + y^2 + xy + x + y
     #       s.t.  x, y >= 0
     #             x + y = 1 (c1)
-    model = JuMP.Model(() -> DiffOpt.diff_optimizer(Ipopt.Optimizer))
+    model = JuMP.Model(() -> DiffOpt.diff_optimizer(HiGHS.Optimizer))
     MOI.set(model, MOI.Silent(), true)
     @variable(model, x ≥ 0)
     @variable(model, y ≥ 0)
@@ -245,7 +244,7 @@ function test_differentiating_non_trivial_convex_qp_jump()
     q = vec(q)
     h = vec(h)
     b = vec(b)
-    model = JuMP.Model(() -> DiffOpt.diff_optimizer(Ipopt.Optimizer))
+    model = JuMP.Model(() -> DiffOpt.diff_optimizer(HiGHS.Optimizer))
     MOI.set(model, MOI.Silent(), true)
     @variable(model, x[1:nz])
     @objective(model, Min, x' * Q * x + q' * x)
diff --git a/test/linear_program.jl b/test/linear_program.jl
index 6d7f709e..865ba7a0 100644
--- a/test/linear_program.jl
+++ b/test/linear_program.jl
@@ -8,7 +8,6 @@ module TestLinearProgram
 using Test
 import DiffOpt
 import HiGHS
-import Ipopt
 import MathOptInterface as MOI
 import SCS
 
@@ -54,7 +53,7 @@ function test_differentiating_a_simple_LP_with_GreaterThan_constraint()
     # s.t. x >= 3
     nz = 1
     qp_test_with_solutions(
-        Ipopt.Optimizer;
+        HiGHS.Optimizer;
         q = ones(nz),
         G = -ones(1, nz),
         h = [-3.0],
diff --git a/test/quadratic_program.jl b/test/quadratic_program.jl
index 31cfa914..c8e9fe03 100644
--- a/test/quadratic_program.jl
+++ b/test/quadratic_program.jl
@@ -9,7 +9,6 @@ using Test
 import DelimitedFiles
 import DiffOpt
 import HiGHS
-import Ipopt
 import MathOptInterface as MOI
 import SCS
 
@@ -43,7 +42,7 @@ function test_forward_on_trivial_QP()
     ]
     h = [1, 0.7, 0.7, -1, 0, 0]
     qp_test_with_solutions(
-        Ipopt.Optimizer;
+        HiGHS.Optimizer;
         Q = Q,
         q = q,
         G = G,
@@ -68,12 +67,12 @@ function test_differentiating_trivial_qp_1()
     G = [1.0 1.0]
     h = [-1.0]
 
-    model = DiffOpt.diff_optimizer(Ipopt.Optimizer)
+    model = DiffOpt.diff_optimizer(HiGHS.Optimizer)
     MOI.set(model, MOI.Silent(), true)
     x = MOI.add_variables(model, 2)
 
     qp_test_with_solutions(
-        Ipopt.Optimizer;
+        HiGHS.Optimizer;
         Q = Q,
         q = q,
         G = G,
@@ -96,7 +95,7 @@ end
 #     G = [1.0 1.0;]
 #     h = [-1.0;]
 #
-#     model = DiffOpt.diff_optimizer(Ipopt.Optimizer)
+#     model = DiffOpt.diff_optimizer(HiGHS.Optimizer)
 #     x = MOI.add_variables(model, 2)
 #
 #     # define objective
@@ -149,7 +148,7 @@ function test_differentiating_qp_with_inequality_and_equality_constraints()
     A = [1.0 1.0 1.0;]
     b = [0.5]
     qp_test_with_solutions(
-        Ipopt.Optimizer;
+        HiGHS.Optimizer;
         Q = Q,
         q = q,
         G = G,
@@ -207,7 +206,7 @@ function test_differentiating_moi_examples_1()
     ]
     dh = [-0.35714284; -0.4285714]
     qp_test_with_solutions(
-        Ipopt.Optimizer;
+        HiGHS.Optimizer;
         Q = Q,
         q = q,
         G = G,
@@ -256,7 +255,7 @@ function test_differentiating_moi_examples_2()
     dA = [0.375 -1.075]
     db = [0.7]
     qp_test_with_solutions(
-        Ipopt.Optimizer;
+        HiGHS.Optimizer;
         Q = Q,
         q = q,
         G = G,
@@ -321,7 +320,7 @@ function test_differentiating_non_trivial_convex_qp_moi()
     dhb = vec(grads_actual[4])
     dbb = vec(grads_actual[6])
     qp_test(
-        Ipopt.Optimizer,
+        HiGHS.Optimizer,
         DiffOpt.QuadraticProgram.Model,
         true,
         true,