diff --git a/tests/fixtures/complete.toml b/tests/fixtures/complete.toml
index ced35cb46e3..74b89b9f3df 100644
--- a/tests/fixtures/complete.toml
+++ b/tests/fixtures/complete.toml
@@ -32,7 +32,7 @@ pendulum = { version = "^1.4", optional = true }
 [tool.poetry.extras]
 time = [ "pendulum" ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "^3.0"
 pytest-cov = "^2.4"
 
diff --git a/tests/fixtures/directory/project_with_transitive_directory_dependencies/pyproject.toml b/tests/fixtures/directory/project_with_transitive_directory_dependencies/pyproject.toml
index 28678e0d0ae..b7ea062a09c 100644
--- a/tests/fixtures/directory/project_with_transitive_directory_dependencies/pyproject.toml
+++ b/tests/fixtures/directory/project_with_transitive_directory_dependencies/pyproject.toml
@@ -10,4 +10,4 @@ python = "*"
 project-with-extras = {path = "../../project_with_extras/"}
 project-with-transitive-file-dependencies = {path = "../project_with_transitive_file_dependencies/"}
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
diff --git a/tests/fixtures/directory/project_with_transitive_file_dependencies/inner-directory-project/pyproject.toml b/tests/fixtures/directory/project_with_transitive_file_dependencies/inner-directory-project/pyproject.toml
index a80113675e6..1b9e242ddff 100644
--- a/tests/fixtures/directory/project_with_transitive_file_dependencies/inner-directory-project/pyproject.toml
+++ b/tests/fixtures/directory/project_with_transitive_file_dependencies/inner-directory-project/pyproject.toml
@@ -8,4 +8,4 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "*"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
diff --git a/tests/fixtures/directory/project_with_transitive_file_dependencies/pyproject.toml b/tests/fixtures/directory/project_with_transitive_file_dependencies/pyproject.toml
index 678e42f2fa5..abd77abe171 100644
--- a/tests/fixtures/directory/project_with_transitive_file_dependencies/pyproject.toml
+++ b/tests/fixtures/directory/project_with_transitive_file_dependencies/pyproject.toml
@@ -10,4 +10,4 @@ python = "*"
 demo = {path = "../../distributions/demo-0.1.0-py2.py3-none-any.whl"}
 inner-directory-project = {path = "./inner-directory-project"}
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
diff --git a/tests/fixtures/excluded_subpackage/pyproject.toml b/tests/fixtures/excluded_subpackage/pyproject.toml
index 3852bb831fa..0c6018291a5 100644
--- a/tests/fixtures/excluded_subpackage/pyproject.toml
+++ b/tests/fixtures/excluded_subpackage/pyproject.toml
@@ -10,7 +10,7 @@ exclude = [
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "^3.0"
 
 [build-system]
diff --git a/tests/fixtures/git/github.com/demo/poetry-plugin/pyproject.toml b/tests/fixtures/git/github.com/demo/poetry-plugin/pyproject.toml
index b45d9d976eb..02891e025fd 100644
--- a/tests/fixtures/git/github.com/demo/poetry-plugin/pyproject.toml
+++ b/tests/fixtures/git/github.com/demo/poetry-plugin/pyproject.toml
@@ -15,4 +15,4 @@ tomlkit = {version = "^0.7.0", optional = true}
 [tool.poetry.extras]
 foo = ["tomlkit"]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
diff --git a/tests/fixtures/git/github.com/demo/poetry-plugin2/subdir/pyproject.toml b/tests/fixtures/git/github.com/demo/poetry-plugin2/subdir/pyproject.toml
index b45d9d976eb..02891e025fd 100644
--- a/tests/fixtures/git/github.com/demo/poetry-plugin2/subdir/pyproject.toml
+++ b/tests/fixtures/git/github.com/demo/poetry-plugin2/subdir/pyproject.toml
@@ -15,4 +15,4 @@ tomlkit = {version = "^0.7.0", optional = true}
 [tool.poetry.extras]
 foo = ["tomlkit"]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
diff --git a/tests/fixtures/git/github.com/demo/prerelease/pyproject.toml b/tests/fixtures/git/github.com/demo/prerelease/pyproject.toml
index b06aef85184..5fa09dd6570 100644
--- a/tests/fixtures/git/github.com/demo/prerelease/pyproject.toml
+++ b/tests/fixtures/git/github.com/demo/prerelease/pyproject.toml
@@ -11,4 +11,4 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "~2.7 || ^3.4"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
diff --git a/tests/fixtures/git/github.com/demo/pyproject-demo/pyproject.toml b/tests/fixtures/git/github.com/demo/pyproject-demo/pyproject.toml
index 70e9f00cb2a..8d710f3786a 100644
--- a/tests/fixtures/git/github.com/demo/pyproject-demo/pyproject.toml
+++ b/tests/fixtures/git/github.com/demo/pyproject-demo/pyproject.toml
@@ -12,4 +12,4 @@ license = "MIT"
 python = "~2.7 || ^3.4"
 pendulum = '^1.4'
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
diff --git a/tests/fixtures/incompatible_lock/pyproject.toml b/tests/fixtures/incompatible_lock/pyproject.toml
index 377aa676be9..d82fbdaa1c8 100644
--- a/tests/fixtures/incompatible_lock/pyproject.toml
+++ b/tests/fixtures/incompatible_lock/pyproject.toml
@@ -8,7 +8,7 @@ authors = ["Poetry Developer <developer@python-poetry.org>"]
 python = "^3.8"
 sampleproject = ">=1.3.1"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/tests/fixtures/inspection/demo/pyproject.toml b/tests/fixtures/inspection/demo/pyproject.toml
index 60c7dc52156..4fd63de9f66 100644
--- a/tests/fixtures/inspection/demo/pyproject.toml
+++ b/tests/fixtures/inspection/demo/pyproject.toml
@@ -14,5 +14,5 @@ tomlkit = {version = "*", optional = true}
 foo = ["cleo"]
 bar = ["tomlkit"]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "^3.0"
diff --git a/tests/fixtures/inspection/demo_poetry_package/pyproject.toml b/tests/fixtures/inspection/demo_poetry_package/pyproject.toml
index 011338ea91a..8bda2638e6f 100644
--- a/tests/fixtures/inspection/demo_poetry_package/pyproject.toml
+++ b/tests/fixtures/inspection/demo_poetry_package/pyproject.toml
@@ -8,7 +8,7 @@ authors = ["John Doe <john@example.com.com>"]
 python = "^3.10"
 pendulum = "*"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/tests/fixtures/inspection/demo_with_obsolete_egg_info/pyproject.toml b/tests/fixtures/inspection/demo_with_obsolete_egg_info/pyproject.toml
index 60c7dc52156..4fd63de9f66 100644
--- a/tests/fixtures/inspection/demo_with_obsolete_egg_info/pyproject.toml
+++ b/tests/fixtures/inspection/demo_with_obsolete_egg_info/pyproject.toml
@@ -14,5 +14,5 @@ tomlkit = {version = "*", optional = true}
 foo = ["cleo"]
 bar = ["tomlkit"]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "^3.0"
diff --git a/tests/fixtures/invalid_lock/pyproject.toml b/tests/fixtures/invalid_lock/pyproject.toml
index 377aa676be9..d82fbdaa1c8 100644
--- a/tests/fixtures/invalid_lock/pyproject.toml
+++ b/tests/fixtures/invalid_lock/pyproject.toml
@@ -8,7 +8,7 @@ authors = ["Poetry Developer <developer@python-poetry.org>"]
 python = "^3.8"
 sampleproject = ">=1.3.1"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/tests/fixtures/missing_directory_dependency/pyproject.toml b/tests/fixtures/missing_directory_dependency/pyproject.toml
index 570ca5debc3..bf10934e9ea 100644
--- a/tests/fixtures/missing_directory_dependency/pyproject.toml
+++ b/tests/fixtures/missing_directory_dependency/pyproject.toml
@@ -9,5 +9,5 @@ packages = []
 [tool.poetry.dependencies]
 python = "*"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 missing = { path = "./missing" }
diff --git a/tests/fixtures/missing_file_dependency/pyproject.toml b/tests/fixtures/missing_file_dependency/pyproject.toml
index 0be727e2104..44e93caa623 100644
--- a/tests/fixtures/missing_file_dependency/pyproject.toml
+++ b/tests/fixtures/missing_file_dependency/pyproject.toml
@@ -9,5 +9,5 @@ packages = []
 [tool.poetry.dependencies]
 python = "*"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 missing = { file = "missing-0.1.0-py2.py3-none-any.whl" }
diff --git a/tests/fixtures/old_lock/pyproject.toml b/tests/fixtures/old_lock/pyproject.toml
index 377aa676be9..d82fbdaa1c8 100644
--- a/tests/fixtures/old_lock/pyproject.toml
+++ b/tests/fixtures/old_lock/pyproject.toml
@@ -8,7 +8,7 @@ authors = ["Poetry Developer <developer@python-poetry.org>"]
 python = "^3.8"
 sampleproject = ">=1.3.1"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/tests/fixtures/old_lock_path_dependency/pyproject.toml b/tests/fixtures/old_lock_path_dependency/pyproject.toml
index 00547cfee26..204f8efb24b 100644
--- a/tests/fixtures/old_lock_path_dependency/pyproject.toml
+++ b/tests/fixtures/old_lock_path_dependency/pyproject.toml
@@ -8,7 +8,7 @@ authors = ["Poetry Developer <developer@python-poetry.org>"]
 python = "^3.8"
 quix = { path = "./quix", develop = true}
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/tests/fixtures/outdated_lock/pyproject.toml b/tests/fixtures/outdated_lock/pyproject.toml
index 555147605ea..257fbe6ea74 100644
--- a/tests/fixtures/outdated_lock/pyproject.toml
+++ b/tests/fixtures/outdated_lock/pyproject.toml
@@ -8,7 +8,7 @@ authors = ["Poetry Developer <developer@python-poetry.org>"]
 python = "^3.8"
 docker = "4.3.1"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/tests/fixtures/project_with_extras/pyproject.toml b/tests/fixtures/project_with_extras/pyproject.toml
index e2ad7619069..230ab85dae9 100644
--- a/tests/fixtures/project_with_extras/pyproject.toml
+++ b/tests/fixtures/project_with_extras/pyproject.toml
@@ -13,5 +13,3 @@ cachy = { version = ">=0.2.0", optional = true }
 [tool.poetry.extras]
 extras_a = [ "pendulum" ]
 extras_b = [ "cachy" ]
-
-[tool.poetry.dev-dependencies]
diff --git a/tests/fixtures/project_with_git_dev_dependency/pyproject.toml b/tests/fixtures/project_with_git_dev_dependency/pyproject.toml
index 57009d822fd..dfee015fe6b 100644
--- a/tests/fixtures/project_with_git_dev_dependency/pyproject.toml
+++ b/tests/fixtures/project_with_git_dev_dependency/pyproject.toml
@@ -24,7 +24,7 @@ python = "~2.7 || ^3.4"
 cachy = "^0.1.0"
 pendulum = "^2.0.0"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 demo = { git = "https://github.com/demo/demo.git", rev = "9cf87a285a2d3fbb0b9fa621997b3acc3631ed24" }
 
diff --git a/tests/fixtures/project_with_multi_constraints_dependency/pyproject.toml b/tests/fixtures/project_with_multi_constraints_dependency/pyproject.toml
index 69462a6ab44..4d609342caf 100644
--- a/tests/fixtures/project_with_multi_constraints_dependency/pyproject.toml
+++ b/tests/fixtures/project_with_multi_constraints_dependency/pyproject.toml
@@ -16,4 +16,4 @@ pendulum = [
     { version = "^2.0", python = "^3.4" }
 ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
diff --git a/tests/fixtures/up_to_date_lock/poetry.lock b/tests/fixtures/up_to_date_lock/poetry.lock
index 4155300cea5..ad184f3353c 100644
--- a/tests/fixtures/up_to_date_lock/poetry.lock
+++ b/tests/fixtures/up_to_date_lock/poetry.lock
@@ -140,4 +140,4 @@ six = "*"
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.8"
-content-hash = "67c4543fd4f299cfeeaf82c5846ce720aa576e49811fbf9ccd0463ac8d5b52e4"
+content-hash = "ff2489c48d3c858a11c1ce7463ae5dc1524d9d457826c1bf16fd687a7bc1e819"
diff --git a/tests/fixtures/up_to_date_lock/pyproject.toml b/tests/fixtures/up_to_date_lock/pyproject.toml
index dd388ab9d00..adaafb9481a 100644
--- a/tests/fixtures/up_to_date_lock/pyproject.toml
+++ b/tests/fixtures/up_to_date_lock/pyproject.toml
@@ -8,7 +8,7 @@ authors = ["Poetry Developer <developer@python-poetry.org>"]
 python = "^3.8"
 docker = ">=4.3.1"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/tests/fixtures/with-include/pyproject.toml b/tests/fixtures/with-include/pyproject.toml
index 07f5f4cf24c..25ec2764d77 100644
--- a/tests/fixtures/with-include/pyproject.toml
+++ b/tests/fixtures/with-include/pyproject.toml
@@ -44,7 +44,7 @@ cachy = { version = "^0.2.0", extras = ["msgpack"] }
 
 pendulum = { version = "^1.4", optional = true }
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 
 [tool.poetry.extras]
diff --git a/tests/fixtures/with_default_source/pyproject.toml b/tests/fixtures/with_default_source/pyproject.toml
index ccda6306bd5..bc0c4ac42b1 100644
--- a/tests/fixtures/with_default_source/pyproject.toml
+++ b/tests/fixtures/with_default_source/pyproject.toml
@@ -43,7 +43,7 @@ simple-project = { path = "../simple_project/" }
 [tool.poetry.extras]
 db = [ "orator" ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 
 
diff --git a/tests/fixtures/with_default_source_and_pypi/pyproject.toml b/tests/fixtures/with_default_source_and_pypi/pyproject.toml
index eb949e6b607..cf7ec689a8f 100644
--- a/tests/fixtures/with_default_source_and_pypi/pyproject.toml
+++ b/tests/fixtures/with_default_source_and_pypi/pyproject.toml
@@ -43,7 +43,7 @@ simple-project = { path = "../simple_project/" }
 [tool.poetry.extras]
 db = [ "orator" ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 
 
diff --git a/tests/fixtures/with_default_source_legacy/pyproject.toml b/tests/fixtures/with_default_source_legacy/pyproject.toml
index ca27c0ce032..b30cc53bda6 100644
--- a/tests/fixtures/with_default_source_legacy/pyproject.toml
+++ b/tests/fixtures/with_default_source_legacy/pyproject.toml
@@ -43,7 +43,7 @@ simple-project = { path = "../simple_project/" }
 [tool.poetry.extras]
 db = [ "orator" ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 
 
diff --git a/tests/fixtures/with_default_source_pypi/pyproject.toml b/tests/fixtures/with_default_source_pypi/pyproject.toml
index 84fba4d7d26..c3fcb9380a6 100644
--- a/tests/fixtures/with_default_source_pypi/pyproject.toml
+++ b/tests/fixtures/with_default_source_pypi/pyproject.toml
@@ -43,7 +43,7 @@ simple-project = { path = "../simple_project/" }
 [tool.poetry.extras]
 db = [ "orator" ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 
 
diff --git a/tests/fixtures/with_explicit_pypi_and_other/pyproject.toml b/tests/fixtures/with_explicit_pypi_and_other/pyproject.toml
index ae588647a56..8605f8ec252 100644
--- a/tests/fixtures/with_explicit_pypi_and_other/pyproject.toml
+++ b/tests/fixtures/with_explicit_pypi_and_other/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_explicit_pypi_and_other_explicit/pyproject.toml b/tests/fixtures/with_explicit_pypi_and_other_explicit/pyproject.toml
index d7666f8836d..86747b64925 100644
--- a/tests/fixtures/with_explicit_pypi_and_other_explicit/pyproject.toml
+++ b/tests/fixtures/with_explicit_pypi_and_other_explicit/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "explicit"
diff --git a/tests/fixtures/with_explicit_pypi_no_other/pyproject.toml b/tests/fixtures/with_explicit_pypi_no_other/pyproject.toml
index 19b38da7904..fed7d4a861e 100644
--- a/tests/fixtures/with_explicit_pypi_no_other/pyproject.toml
+++ b/tests/fixtures/with_explicit_pypi_no_other/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "PyPI"
diff --git a/tests/fixtures/with_explicit_source/pyproject.toml b/tests/fixtures/with_explicit_source/pyproject.toml
index c1fde4fffdc..1cdbf537727 100644
--- a/tests/fixtures/with_explicit_source/pyproject.toml
+++ b/tests/fixtures/with_explicit_source/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "explicit"
diff --git a/tests/fixtures/with_local_config/pyproject.toml b/tests/fixtures/with_local_config/pyproject.toml
index 4b814556799..0feb2bcaf00 100644
--- a/tests/fixtures/with_local_config/pyproject.toml
+++ b/tests/fixtures/with_local_config/pyproject.toml
@@ -43,7 +43,7 @@ simple-project = { path = "../simple_project/" }
 [tool.poetry.extras]
 db = [ "orator" ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 
 
diff --git a/tests/fixtures/with_non_default_multiple_secondary_sources/pyproject.toml b/tests/fixtures/with_non_default_multiple_secondary_sources/pyproject.toml
index 1ee7df9444e..517c37cc176 100644
--- a/tests/fixtures/with_non_default_multiple_secondary_sources/pyproject.toml
+++ b/tests/fixtures/with_non_default_multiple_secondary_sources/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_non_default_multiple_secondary_sources_legacy/pyproject.toml b/tests/fixtures/with_non_default_multiple_secondary_sources_legacy/pyproject.toml
index 35bcfd58126..366db7461a8 100644
--- a/tests/fixtures/with_non_default_multiple_secondary_sources_legacy/pyproject.toml
+++ b/tests/fixtures/with_non_default_multiple_secondary_sources_legacy/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_non_default_multiple_sources/pyproject.toml b/tests/fixtures/with_non_default_multiple_sources/pyproject.toml
index f83aeda2da4..b3063e47827 100644
--- a/tests/fixtures/with_non_default_multiple_sources/pyproject.toml
+++ b/tests/fixtures/with_non_default_multiple_sources/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_non_default_multiple_sources_legacy/pyproject.toml b/tests/fixtures/with_non_default_multiple_sources_legacy/pyproject.toml
index e2da526ef39..61f8e9bc59d 100644
--- a/tests/fixtures/with_non_default_multiple_sources_legacy/pyproject.toml
+++ b/tests/fixtures/with_non_default_multiple_sources_legacy/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_non_default_multiple_sources_pypi/pyproject.toml b/tests/fixtures/with_non_default_multiple_sources_pypi/pyproject.toml
index 66db604c4f1..9e71ff764c8 100644
--- a/tests/fixtures/with_non_default_multiple_sources_pypi/pyproject.toml
+++ b/tests/fixtures/with_non_default_multiple_sources_pypi/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_non_default_secondary_source/pyproject.toml b/tests/fixtures/with_non_default_secondary_source/pyproject.toml
index 8dbca2435b7..7a8004cac32 100644
--- a/tests/fixtures/with_non_default_secondary_source/pyproject.toml
+++ b/tests/fixtures/with_non_default_secondary_source/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_non_default_secondary_source_legacy/pyproject.toml b/tests/fixtures/with_non_default_secondary_source_legacy/pyproject.toml
index 2e997cefec7..980d78eecc9 100644
--- a/tests/fixtures/with_non_default_secondary_source_legacy/pyproject.toml
+++ b/tests/fixtures/with_non_default_secondary_source_legacy/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_non_default_source_explicit/pyproject.toml b/tests/fixtures/with_non_default_source_explicit/pyproject.toml
index 3a83099313b..3d6b43c9ca5 100644
--- a/tests/fixtures/with_non_default_source_explicit/pyproject.toml
+++ b/tests/fixtures/with_non_default_source_explicit/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_non_default_source_implicit/pyproject.toml b/tests/fixtures/with_non_default_source_implicit/pyproject.toml
index 73f95041e67..e341a006a89 100644
--- a/tests/fixtures/with_non_default_source_implicit/pyproject.toml
+++ b/tests/fixtures/with_non_default_source_implicit/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "foo"
diff --git a/tests/fixtures/with_supplemental_source/pyproject.toml b/tests/fixtures/with_supplemental_source/pyproject.toml
index 00ae71beb1a..339de55c5e0 100644
--- a/tests/fixtures/with_supplemental_source/pyproject.toml
+++ b/tests/fixtures/with_supplemental_source/pyproject.toml
@@ -11,7 +11,7 @@ license = "MIT"
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 
 [[tool.poetry.source]]
 name = "supplemental"
diff --git a/tests/fixtures/with_two_default_sources/pyproject.toml b/tests/fixtures/with_two_default_sources/pyproject.toml
index d7f5b258ae4..6f05f22eba1 100644
--- a/tests/fixtures/with_two_default_sources/pyproject.toml
+++ b/tests/fixtures/with_two_default_sources/pyproject.toml
@@ -43,7 +43,7 @@ simple-project = { path = "../simple_project/" }
 [tool.poetry.extras]
 db = [ "orator" ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 
 
diff --git a/tests/fixtures/with_two_default_sources_legacy/pyproject.toml b/tests/fixtures/with_two_default_sources_legacy/pyproject.toml
index ffbb22fc70a..0de036eb8c8 100644
--- a/tests/fixtures/with_two_default_sources_legacy/pyproject.toml
+++ b/tests/fixtures/with_two_default_sources_legacy/pyproject.toml
@@ -43,7 +43,7 @@ simple-project = { path = "../simple_project/" }
 [tool.poetry.extras]
 db = [ "orator" ]
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"
 
 
diff --git a/tests/masonry/builders/fixtures/excluded_subpackage/pyproject.toml b/tests/masonry/builders/fixtures/excluded_subpackage/pyproject.toml
index 3852bb831fa..0c6018291a5 100644
--- a/tests/masonry/builders/fixtures/excluded_subpackage/pyproject.toml
+++ b/tests/masonry/builders/fixtures/excluded_subpackage/pyproject.toml
@@ -10,7 +10,7 @@ exclude = [
 [tool.poetry.dependencies]
 python = "^3.6"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "^3.0"
 
 [build-system]
diff --git a/tests/utils/fixtures/pyproject.toml b/tests/utils/fixtures/pyproject.toml
index 09455111204..4a3245be771 100644
--- a/tests/utils/fixtures/pyproject.toml
+++ b/tests/utils/fixtures/pyproject.toml
@@ -24,5 +24,5 @@ toml = "^0.9"
 cachy = "^0.1.0"
 pip-tools = "^1.11"
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.group.dev.dependencies]
 pytest = "~3.4"