diff --git a/MANIFEST.in b/MANIFEST.in
index 5e22a597..4b76c329 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -21,6 +21,7 @@ include testdata/workflows/*.cwl
 include testdata/workflows/*.yaml
 include testdata/types/*.yml
 include testdata/checker_wf/*.cwl
+include testdata/extensions/*.cwl
 include cwl_utils/py.typed
 include docs/conf.py docs/Makefile docs/_static/favicon.ico docs/requirements.txt
 include docs/*.rst
diff --git a/pyproject.toml b/pyproject.toml
index 1c4ba78a..4519fb4e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -67,6 +67,7 @@ packages = [
     "cwl_utils.tests",
     "cwl_utils.testdata",
     "cwl_utils.testdata.checker_wf",
+    "cwl_utils.testdata.extensions",
     "cwl_utils.testdata.types",
     "cwl_utils.testdata.workflows",
 ]
@@ -77,6 +78,7 @@ include-package-data = true
 "cwl_utils.tests" = "tests"
 "cwl_utils.testdata" = "testdata"
 "cwl_utils.testdata.checker_wf" = "testdata/checker_wf"
+"cwl_utils.testdata.extensions" = "testdata/extensions"
 "cwl_utils.testdata.types" = "testdata/types"
 "cwl_utils.testdata.workflows" = "testdata/workflows"
 
diff --git a/requirements.txt b/requirements.txt
index 3eac45ed..d24b7145 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,5 +2,5 @@ cwl-upgrader >= 1.2.3
 packaging
 rdflib
 requests
-schema-salad @ git+https://github.com/common-workflow-language/schema_salad.git
+schema-salad >= 8.8.20241206093842, < 9
 ruamel.yaml >= 0.17.6, < 0.19
diff --git a/testdata/extensions/all-output-loop_v1_2.cwl b/testdata/extensions/all-output-loop_v1_2.cwl
new file mode 100644
index 00000000..096be519
--- /dev/null
+++ b/testdata/extensions/all-output-loop_v1_2.cwl
@@ -0,0 +1,32 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.2
+class: Workflow
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  InlineJavascriptRequirement: {}
+inputs:
+  i1: int
+outputs:
+  o1:
+    type: int[]
+    outputSource: subworkflow/o1
+steps:
+  subworkflow:
+    run:
+      class: ExpressionTool
+      inputs:
+        i1: int
+      outputs:
+        o1: int
+      expression: >
+        ${return {'o1': inputs.i1 + 1};}
+    in:
+      i1: i1
+    out: [o1]
+    requirements:
+      cwltool:Loop:
+        loopWhen: $(inputs.i1 < 10)
+        loop:
+          i1: o1
+        outputMethod: all
diff --git a/testdata/extensions/cuda-requirement_v1_0.cwl b/testdata/extensions/cuda-requirement_v1_0.cwl
new file mode 100644
index 00000000..21985e6c
--- /dev/null
+++ b/testdata/extensions/cuda-requirement_v1_0.cwl
@@ -0,0 +1,16 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.0
+class: CommandLineTool
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:CUDARequirement:
+    cudaVersionMin: "1.0"
+    cudaComputeCapability: "1.0"
+    cudaDeviceCountMin: $(inputs.gpus)
+inputs:
+  gpus:
+    type: int
+    default: 1
+outputs: []
+baseCommand: "nvidia-smi"
\ No newline at end of file
diff --git a/testdata/extensions/cuda-requirement_v1_1.cwl b/testdata/extensions/cuda-requirement_v1_1.cwl
new file mode 100644
index 00000000..9c24f0fe
--- /dev/null
+++ b/testdata/extensions/cuda-requirement_v1_1.cwl
@@ -0,0 +1,16 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.1
+class: CommandLineTool
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:CUDARequirement:
+    cudaVersionMin: "1.0"
+    cudaComputeCapability: "1.0"
+    cudaDeviceCountMin: $(inputs.gpus)
+inputs:
+  gpus:
+    type: int
+    default: 1
+outputs: []
+baseCommand: "nvidia-smi"
\ No newline at end of file
diff --git a/testdata/extensions/cuda-requirement_v1_2.cwl b/testdata/extensions/cuda-requirement_v1_2.cwl
new file mode 100644
index 00000000..4f1ecbd8
--- /dev/null
+++ b/testdata/extensions/cuda-requirement_v1_2.cwl
@@ -0,0 +1,16 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.2
+class: CommandLineTool
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:CUDARequirement:
+    cudaVersionMin: "1.0"
+    cudaComputeCapability: "1.0"
+    cudaDeviceCountMin: $(inputs.gpus)
+inputs:
+  gpus:
+    type: int
+    default: 1
+outputs: []
+baseCommand: "nvidia-smi"
\ No newline at end of file
diff --git a/testdata/extensions/inplace-update-requirement_v1_0.cwl b/testdata/extensions/inplace-update-requirement_v1_0.cwl
new file mode 100644
index 00000000..14f72054
--- /dev/null
+++ b/testdata/extensions/inplace-update-requirement_v1_0.cwl
@@ -0,0 +1,21 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.0
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:InplaceUpdateRequirement:
+    inplaceUpdate: true
+inputs:
+  r: File
+  script:
+    type: File
+    default:
+      class: File
+      location: updateval.py
+outputs:
+  out:
+    type: File
+    outputBinding:
+      glob: $(inputs.r.basename)
+arguments: [python, $(inputs.script), $(inputs.r.basename)]
\ No newline at end of file
diff --git a/testdata/extensions/load-listing-requirement_v1_0.cwl b/testdata/extensions/load-listing-requirement_v1_0.cwl
new file mode 100644
index 00000000..36d67fb4
--- /dev/null
+++ b/testdata/extensions/load-listing-requirement_v1_0.cwl
@@ -0,0 +1,13 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.0
+$namespaces:
+  cwltool: http://commonwl.org/cwltool#
+requirements:
+  cwltool:LoadListingRequirement:
+    loadListing: shallow_listing
+inputs:
+  d: Directory
+outputs: []
+arguments:
+  [echo, "$(inputs.d.listing[0].listing[0])"]
diff --git a/testdata/extensions/mpi-requirement_v1_0.cwl b/testdata/extensions/mpi-requirement_v1_0.cwl
new file mode 100644
index 00000000..72dc680b
--- /dev/null
+++ b/testdata/extensions/mpi-requirement_v1_0.cwl
@@ -0,0 +1,14 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.0
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+
+baseCommand: env
+requirements:
+  cwltool:MPIRequirement:
+    processes: 1
+inputs: {}
+outputs:
+  environment:
+    type: stdout
\ No newline at end of file
diff --git a/testdata/extensions/mpi-requirement_v1_1.cwl b/testdata/extensions/mpi-requirement_v1_1.cwl
new file mode 100644
index 00000000..a4ad0fe1
--- /dev/null
+++ b/testdata/extensions/mpi-requirement_v1_1.cwl
@@ -0,0 +1,13 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.1
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+baseCommand: env
+requirements:
+  cwltool:MPIRequirement:
+    processes: 1
+inputs: {}
+outputs:
+  environment:
+    type: stdout
\ No newline at end of file
diff --git a/testdata/extensions/mpi-requirement_v1_2.cwl b/testdata/extensions/mpi-requirement_v1_2.cwl
new file mode 100644
index 00000000..5790f414
--- /dev/null
+++ b/testdata/extensions/mpi-requirement_v1_2.cwl
@@ -0,0 +1,13 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.2
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+baseCommand: env
+requirements:
+  cwltool:MPIRequirement:
+    processes: 1
+inputs: {}
+outputs:
+  environment:
+    type: stdout
\ No newline at end of file
diff --git a/testdata/extensions/network-access_v1_0.cwl b/testdata/extensions/network-access_v1_0.cwl
new file mode 100644
index 00000000..4152a116
--- /dev/null
+++ b/testdata/extensions/network-access_v1_0.cwl
@@ -0,0 +1,16 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.0
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:NetworkAccess:
+    networkAccess: true
+inputs: []
+outputs: []
+baseCommand: python
+arguments:
+  - "-c"
+  - valueFrom: |
+      import urllib.request
+      assert(urllib.request.urlopen("http://commonwl.org").code == 200)
\ No newline at end of file
diff --git a/testdata/extensions/process-generator_v1_0.cwl b/testdata/extensions/process-generator_v1_0.cwl
new file mode 100644
index 00000000..01df6367
--- /dev/null
+++ b/testdata/extensions/process-generator_v1_0.cwl
@@ -0,0 +1,32 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.0
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+class: cwltool:ProcessGenerator
+inputs:
+  script: string
+  dir: Directory
+outputs: {}
+run:
+  class: CommandLineTool
+  inputs:
+    script: string
+    dir: Directory
+  outputs:
+    runProcess:
+      type: File
+      outputBinding:
+        glob: main.cwl
+  requirements:
+    InlineJavascriptRequirement: {}
+    LoadListingRequirement:
+      loadListing: shallow_listing
+    InitialWorkDirRequirement:
+      listing: |
+        ${
+         var v = inputs.dir.listing;
+         v.push({entryname: "inp.py", entry: inputs.script});
+         return v;
+        }
+  arguments: [python3, inp.py]
+  stdout: main.cwl
\ No newline at end of file
diff --git a/testdata/extensions/process-generator_v1_1.cwl b/testdata/extensions/process-generator_v1_1.cwl
new file mode 100644
index 00000000..b4ccc99c
--- /dev/null
+++ b/testdata/extensions/process-generator_v1_1.cwl
@@ -0,0 +1,32 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.1
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+class: cwltool:ProcessGenerator
+inputs:
+  script: string
+  dir: Directory
+outputs: {}
+run:
+  class: CommandLineTool
+  inputs:
+    script: string
+    dir: Directory
+  outputs:
+    runProcess:
+      type: File
+      outputBinding:
+        glob: main.cwl
+  requirements:
+    InlineJavascriptRequirement: {}
+    LoadListingRequirement:
+      loadListing: shallow_listing
+    InitialWorkDirRequirement:
+      listing: |
+        ${
+         var v = inputs.dir.listing;
+         v.push({entryname: "inp.py", entry: inputs.script});
+         return v;
+        }
+  arguments: [python3, inp.py]
+  stdout: main.cwl
\ No newline at end of file
diff --git a/testdata/extensions/process-generator_v1_2.cwl b/testdata/extensions/process-generator_v1_2.cwl
new file mode 100644
index 00000000..62960a2f
--- /dev/null
+++ b/testdata/extensions/process-generator_v1_2.cwl
@@ -0,0 +1,32 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.2
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+class: cwltool:ProcessGenerator
+inputs:
+  script: string
+  dir: Directory
+outputs: {}
+run:
+  class: CommandLineTool
+  inputs:
+    script: string
+    dir: Directory
+  outputs:
+    runProcess:
+      type: File
+      outputBinding:
+        glob: main.cwl
+  requirements:
+    InlineJavascriptRequirement: {}
+    LoadListingRequirement:
+      loadListing: shallow_listing
+    InitialWorkDirRequirement:
+      listing: |
+        ${
+         var v = inputs.dir.listing;
+         v.push({entryname: "inp.py", entry: inputs.script});
+         return v;
+        }
+  arguments: [python3, inp.py]
+  stdout: main.cwl
\ No newline at end of file
diff --git a/testdata/extensions/secrets_v1_0.cwl b/testdata/extensions/secrets_v1_0.cwl
new file mode 100644
index 00000000..63446512
--- /dev/null
+++ b/testdata/extensions/secrets_v1_0.cwl
@@ -0,0 +1,13 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.0
+class: CommandLineTool
+$namespaces:
+  cwltool: http://commonwl.org/cwltool#
+requirements:
+  cwltool:Secrets:
+    secrets: [pw]
+inputs:
+  pw: string
+outputs:
+  out: stdout
+arguments: [cat, example.conf]
diff --git a/testdata/extensions/secrets_v1_1.cwl b/testdata/extensions/secrets_v1_1.cwl
new file mode 100644
index 00000000..09d476f6
--- /dev/null
+++ b/testdata/extensions/secrets_v1_1.cwl
@@ -0,0 +1,13 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.1
+class: CommandLineTool
+$namespaces:
+  cwltool: http://commonwl.org/cwltool#
+requirements:
+  cwltool:Secrets:
+    secrets: [pw]
+inputs:
+  pw: string
+outputs:
+  out: stdout
+arguments: [cat, example.conf]
diff --git a/testdata/extensions/secrets_v1_2.cwl b/testdata/extensions/secrets_v1_2.cwl
new file mode 100644
index 00000000..02d7dff6
--- /dev/null
+++ b/testdata/extensions/secrets_v1_2.cwl
@@ -0,0 +1,13 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.2
+class: CommandLineTool
+$namespaces:
+  cwltool: http://commonwl.org/cwltool#
+requirements:
+  cwltool:Secrets:
+    secrets: [pw]
+inputs:
+  pw: string
+outputs:
+  out: stdout
+arguments: [cat, example.conf]
diff --git a/testdata/extensions/shm-size_v1_0.cwl b/testdata/extensions/shm-size_v1_0.cwl
new file mode 100644
index 00000000..01f90a44
--- /dev/null
+++ b/testdata/extensions/shm-size_v1_0.cwl
@@ -0,0 +1,15 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.0
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:ShmSize:
+    shmSize: 128m
+inputs: []
+outputs:
+  output:
+    type: stdout
+baseCommand: echo
+stdout: shm-size.txt
+arguments: [ $(runtime) ]
diff --git a/testdata/extensions/shm-size_v1_1.cwl b/testdata/extensions/shm-size_v1_1.cwl
new file mode 100644
index 00000000..3bff20df
--- /dev/null
+++ b/testdata/extensions/shm-size_v1_1.cwl
@@ -0,0 +1,15 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.1
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:ShmSize:
+    shmSize: 128m
+inputs: []
+outputs:
+  output:
+    type: stdout
+baseCommand: echo
+stdout: shm-size.txt
+arguments: [ $(runtime) ]
diff --git a/testdata/extensions/shm-size_v1_2.cwl b/testdata/extensions/shm-size_v1_2.cwl
new file mode 100644
index 00000000..b6491432
--- /dev/null
+++ b/testdata/extensions/shm-size_v1_2.cwl
@@ -0,0 +1,15 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.2
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:ShmSize:
+    shmSize: 128m
+inputs: []
+outputs:
+  output:
+    type: stdout
+baseCommand: echo
+stdout: shm-size.txt
+arguments: [ $(runtime) ]
diff --git a/testdata/extensions/single-var-loop_v1_2.cwl b/testdata/extensions/single-var-loop_v1_2.cwl
new file mode 100644
index 00000000..c5f76563
--- /dev/null
+++ b/testdata/extensions/single-var-loop_v1_2.cwl
@@ -0,0 +1,32 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.2
+class: Workflow
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  InlineJavascriptRequirement: {}
+inputs:
+  i1: int
+outputs:
+  o1:
+    type: int
+    outputSource: subworkflow/o1
+steps:
+  subworkflow:
+    run:
+      class: ExpressionTool
+      inputs:
+        i1: int
+      outputs:
+        o1: int
+      expression: >
+        ${return {'o1': inputs.i1 + 1};}
+    in:
+      i1: i1
+    out: [o1]
+    requirements:
+      cwltool:Loop:
+        loopWhen: $(inputs.i1 < 10)
+        loop:
+          i1: o1
+        outputMethod: last
diff --git a/testdata/extensions/time-limit_v1_0.cwl b/testdata/extensions/time-limit_v1_0.cwl
new file mode 100644
index 00000000..7106a934
--- /dev/null
+++ b/testdata/extensions/time-limit_v1_0.cwl
@@ -0,0 +1,15 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.0
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+inputs:
+  sleep_time:
+    type: int
+    default: 3
+    inputBinding: {}
+outputs: []
+requirements:
+  cwltool:TimeLimit:
+    timelimit: 20
+baseCommand: sleep
\ No newline at end of file
diff --git a/testdata/extensions/work-reuse_v1_0.cwl b/testdata/extensions/work-reuse_v1_0.cwl
new file mode 100644
index 00000000..7278cb2b
--- /dev/null
+++ b/testdata/extensions/work-reuse_v1_0.cwl
@@ -0,0 +1,18 @@
+#!/usr/bin/env cwl-runner
+class: CommandLineTool
+cwlVersion: v1.0
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  cwltool:WorkReuse:
+    enableReuse: false
+inputs: []
+outputs:
+  page: stdout
+stdout: time.txt
+baseCommand: python
+arguments:
+  - "-c"
+  - valueFrom: |
+      import time
+      print(time.time())
diff --git a/tests/test_extensions.py b/tests/test_extensions.py
new file mode 100644
index 00000000..ab4a0f43
--- /dev/null
+++ b/tests/test_extensions.py
@@ -0,0 +1,204 @@
+from pathlib import Path
+
+from cwl_utils.parser import cwl_v1_0, cwl_v1_1, cwl_v1_2, load_document_by_uri
+
+from .util import get_data
+
+
+def test_cuda_requirement_v1_0() -> None:
+    """Test that CUDARequirement objects are correctly loaded for CWL v1.0."""
+    uri = (
+        Path(get_data("testdata/extensions/cuda-requirement_v1_0.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_0.CUDARequirement)
+
+
+def test_cuda_requirement_v1_1() -> None:
+    """Test that CUDARequirement objects are correctly loaded for CWL v1.1."""
+    uri = (
+        Path(get_data("testdata/extensions/cuda-requirement_v1_1.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_1.CUDARequirement)
+
+
+def test_cuda_requirement_v1_2() -> None:
+    """Test that CUDARequirement objects are correctly loaded for CWL v1.2."""
+    uri = (
+        Path(get_data("testdata/extensions/cuda-requirement_v1_2.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_2.CUDARequirement)
+
+
+def test_load_listing_requirement_v1_0() -> None:
+    """Test that LoadListingRequirement objects are correctly loaded for CWL v1.0."""
+    uri = (
+        Path(get_data("testdata/extensions/load-listing-requirement_v1_0.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_0.LoadListingRequirement)
+
+
+def test_loop_v1_2() -> None:
+    """Test that Loop and LoopInput objects are correctly loaded for CWL v1.2."""
+    uri = (
+        Path(get_data("testdata/extensions/single-var-loop_v1_2.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    cwl_step = next(iter(cwl_obj.steps))
+    loop_req = next(iter(cwl_step.requirements))
+    assert isinstance(loop_req, cwl_v1_2.Loop)
+    assert isinstance(next(iter(loop_req.loop)), cwl_v1_2.LoopInput)
+
+
+def test_inplace_update_requirement_v1_0() -> None:
+    """Test that InplaceUpdateRequirement objects are correctly loaded for CWL v1.0."""
+    uri = (
+        Path(get_data("testdata/extensions/inplace-update-requirement_v1_0.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(
+        next(iter(cwl_obj.requirements)), cwl_v1_0.InplaceUpdateRequirement
+    )
+
+
+def test_mpi_requirement_v1_0() -> None:
+    """Test that MPIRequirement objects are correctly loaded for CWL v1.0."""
+    uri = (
+        Path(get_data("testdata/extensions/mpi-requirement_v1_0.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_0.MPIRequirement)
+
+
+def test_mpi_requirement_v1_1() -> None:
+    """Test that MPIRequirement objects are correctly loaded for CWL v1.1."""
+    uri = (
+        Path(get_data("testdata/extensions/mpi-requirement_v1_1.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_1.MPIRequirement)
+
+
+def test_mpi_requirement_v1_2() -> None:
+    """Test that MPIRequirement objects are correctly loaded for CWL v1.2."""
+    uri = (
+        Path(get_data("testdata/extensions/mpi-requirement_v1_2.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_2.MPIRequirement)
+
+
+def test_network_access_v1_0() -> None:
+    """Test that NetworkAccess objects are correctly loaded for CWL v1.0."""
+    uri = (
+        Path(get_data("testdata/extensions/network-access_v1_0.cwl")).resolve().as_uri()
+    )
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_0.NetworkAccess)
+
+
+def test_process_generator_v1_0() -> None:
+    """Test that ProcessGenerator objects are correctly loaded for CWL v1.0."""
+    uri = (
+        Path(get_data("testdata/extensions/process-generator_v1_0.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    assert isinstance(load_document_by_uri(uri), cwl_v1_0.ProcessGenerator)
+
+
+def test_process_generator_v1_1() -> None:
+    """Test that ProcessGenerator objects are correctly loaded for CWL v1.1."""
+    uri = (
+        Path(get_data("testdata/extensions/process-generator_v1_1.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    assert isinstance(load_document_by_uri(uri), cwl_v1_1.ProcessGenerator)
+
+
+def test_process_generator_v1_2() -> None:
+    """Test that ProcessGenerator objects are correctly loaded for CWL v1.2."""
+    uri = (
+        Path(get_data("testdata/extensions/process-generator_v1_2.cwl"))
+        .resolve()
+        .as_uri()
+    )
+    assert isinstance(load_document_by_uri(uri), cwl_v1_2.ProcessGenerator)
+
+
+def test_secrets_v1_0() -> None:
+    """Test that Secrets objects are correctly loaded for CWL v1.0."""
+    uri = Path(get_data("testdata/extensions/secrets_v1_0.cwl")).resolve().as_uri()
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_0.Secrets)
+
+
+def test_secrets_v1_1() -> None:
+    """Test that Secrets objects are correctly loaded for CWL v1.1."""
+    uri = Path(get_data("testdata/extensions/secrets_v1_1.cwl")).resolve().as_uri()
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_1.Secrets)
+
+
+def test_secrets_v1_2() -> None:
+    """Test that Secrets objects are correctly loaded for CWL v1.2."""
+    uri = Path(get_data("testdata/extensions/secrets_v1_2.cwl")).resolve().as_uri()
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_2.Secrets)
+
+
+def test_shm_size_v1_0() -> None:
+    """Test that ShmSize objects are correctly loaded for CWL v1.0."""
+    uri = Path(get_data("testdata/extensions/shm-size_v1_0.cwl")).resolve().as_uri()
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_0.ShmSize)
+
+
+def test_shm_size_v1_1() -> None:
+    """Test that ShmSize objects are correctly loaded for CWL v1.1."""
+    uri = Path(get_data("testdata/extensions/shm-size_v1_1.cwl")).resolve().as_uri()
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_1.ShmSize)
+
+
+def test_shm_size_v1_2() -> None:
+    """Test that ShmSize objects are correctly loaded for CWL v1.2."""
+    uri = Path(get_data("testdata/extensions/shm-size_v1_2.cwl")).resolve().as_uri()
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_2.ShmSize)
+
+
+def test_time_limit_v1_0() -> None:
+    """Test that TimeLimit objects are correctly loaded for CWL v1.0."""
+    uri = Path(get_data("testdata/extensions/time-limit_v1_0.cwl")).resolve().as_uri()
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_0.TimeLimit)
+
+
+def test_work_reuse_v1_0() -> None:
+    """Test that WorkReuse objects are correctly loaded for CWL v1.0."""
+    uri = Path(get_data("testdata/extensions/work-reuse_v1_0.cwl")).resolve().as_uri()
+    cwl_obj = load_document_by_uri(uri)
+    assert isinstance(next(iter(cwl_obj.requirements)), cwl_v1_0.WorkReuse)
diff --git a/tests/test_parser_utils.py b/tests/test_parser_utils.py
index e52302a5..8c16b004 100644
--- a/tests/test_parser_utils.py
+++ b/tests/test_parser_utils.py
@@ -103,6 +103,8 @@ def test_static_checker_success(cwlVersion: str) -> None:
                 "testdata/cond-wf-004.1.cwl",
                 "testdata/cond-wf-005.1.cwl",
                 "testdata/cond-single-source-wf-005.1.cwl",
+                "testdata/extensions/all-output-loop_v1_2.cwl",
+                "testdata/extensions/single-var-loop_v1_2.cwl",
             ]
         )
     for test_file in test_files: