diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8728d06747f..782f28ec034 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -164,6 +164,7 @@ jobs:
           - macos-latest
           - ubuntu-latest
           - ubuntu-24.04-arm
+      fail-fast: false
 
     runs-on: ${{ matrix.os }}
 
@@ -184,6 +185,76 @@ jobs:
       - name: Check that tracked archives are up to date
         run: git diff --exit-code  # If this fails, the fix is usually to commit a regenerated archive.
 
+  # TODO(integration): Remove all or at least most test-ext4-casefold jobs prior to merging #2008.
+  test-ext4-casefold:
+    strategy:
+      matrix:
+        # `--test-threads` operand
+        parallel-tests:
+          - 1  # Never fails.
+          - 2  # Usually fails.
+          - 3  # Almost never fails, somehow!
+          - 4  # Usually fails.
+        # Duplicate jobs
+        rep: [A, B, C, D, E, F, G]
+      fail-fast: false
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Warn if we could use tmpfs mounted with `-o casefold` instead
+        run: |
+          case "$(cat </sys/fs/tmpfs/features/casefold || :)" in
+          supported)
+            echo '::warning:: The runner OS supports case-folding tmpfs, which may be preferable.'
+            ;;
+          esac
+      - name: Set up casefold directory
+        run: |
+          set -ux
+          dd if=/dev/zero of=~/ext4-casefold.img bs=100M count=150
+          mkfs.ext4 -O casefold -- ~/ext4-casefold.img
+          mkdir -- ~/ext4-casefold
+          sudo mount -- ~/ext4-casefold.img ~/ext4-casefold
+          sudo chown -- "$USER" ~/ext4-casefold
+          mkdir -- ~/ext4-casefold/icase
+          chattr +F -- ~/ext4-casefold/icase
+      - name: Arrange to map workspace and TMPDIR in all subsequent steps
+        run: |
+          set -ux
+          mkdir -- ~/ext4-casefold/icase/{workspace,tmp}
+          sudo mount --rbind -- ~/ext4-casefold/icase/workspace .
+          printf 'TMPDIR=%s\n' ~/ext4-casefold/icase/tmp >> "$GITHUB_ENV"
+      - name: Verify case folding in workspace and TMPDIR
+        run: |
+          set -ux
+          shopt -s nullglob
+          verify() {
+            touch a A
+            files=(?)
+            test "${#files[@]}" -eq 1
+            rm a
+          }
+          verify
+          (cd -- "$TMPDIR"; verify)
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: taiki-e/install-action@v2
+        with:
+          tool: nextest
+      - name: Increase writes_through_symlinks_are_prevented_even_if_overwriting_is_allowed reps
+        run: |
+          # Prepend leading digits "24" to the upper bound of the label range.
+          sed -Ei 's/^(#\[test_matrix\(0\.\.=)([[:digit:]]+\)])$/\124\2/' \
+            gix-worktree-state/tests/state/checkout.rs
+      - name: Display the changes made for this test
+        run: git diff
+      - name: Test writes_through_symlinks_are_prevented_even_if_overwriting_is_allowed (nextest)
+        run: |
+          cargo nextest run -p gix-worktree-state-tests --no-default-features \
+            writes_through_symlinks_are_prevented_even_if_overwriting_is_allowed \
+            --status-level=fail --test-threads=${{ matrix.parallel-tests }}
+
   test-fixtures-windows:
     runs-on: windows-latest
 
@@ -496,6 +567,7 @@ jobs:
       - test
       - test-journey
       - test-fast
+      - test-ext4-casefold
       - test-fixtures-windows
       - test-32bit
       - test-32bit-windows-size-doc
diff --git a/Cargo.lock b/Cargo.lock
index a154c740c80..3e6feba3de8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2600,6 +2600,7 @@ dependencies = [
  "gix-worktree-state",
  "once_cell",
  "symlink",
+ "test-case",
  "walkdir",
 ]
 
@@ -4757,6 +4758,39 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f50febec83f5ee1df3015341d8bd429f2d1cc62bcba7ea2076759d315084683"
 
+[[package]]
+name = "test-case"
+version = "3.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eb2550dd13afcd286853192af8601920d959b14c401fcece38071d53bf0768a8"
+dependencies = [
+ "test-case-macros",
+]
+
+[[package]]
+name = "test-case-core"
+version = "3.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "adcb7fd841cd518e279be3d5a3eb0636409487998a4aff22f3de87b81e88384f"
+dependencies = [
+ "cfg-if",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.101",
+]
+
+[[package]]
+name = "test-case-macros"
+version = "3.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c89e72a01ed4c579669add59014b9a524d609c0c88c6a585ce37485879f6ffb"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.101",
+ "test-case-core",
+]
+
 [[package]]
 name = "thiserror"
 version = "1.0.69"
diff --git a/gix-worktree-state/tests/Cargo.toml b/gix-worktree-state/tests/Cargo.toml
index 7f41c26467b..e4e5e0fba17 100644
--- a/gix-worktree-state/tests/Cargo.toml
+++ b/gix-worktree-state/tests/Cargo.toml
@@ -33,3 +33,4 @@ symlink = "0.1.0"
 once_cell = "1.21.3"
 
 walkdir = "2.3.2"
+test-case = "3.3.1"
diff --git a/gix-worktree-state/tests/state/checkout.rs b/gix-worktree-state/tests/state/checkout.rs
index 764b52020d3..506b6471e06 100644
--- a/gix-worktree-state/tests/state/checkout.rs
+++ b/gix-worktree-state/tests/state/checkout.rs
@@ -12,6 +12,7 @@ use gix_object::{bstr::ByteSlice, Data};
 use gix_testtools::tempfile::TempDir;
 use gix_worktree_state::checkout::Collision;
 use once_cell::sync::Lazy;
+use test_case::test_matrix;
 
 use crate::fixture_path;
 
@@ -103,8 +104,8 @@ fn accidental_writes_through_symlinks_are_prevented_if_overwriting_is_forbidden(
     }
 }
 
-#[test]
-fn writes_through_symlinks_are_prevented_even_if_overwriting_is_allowed() {
+#[test_matrix(0..=999)]
+fn writes_through_symlinks_are_prevented_even_if_overwriting_is_allowed(_i: i32) {
     let mut opts = opts_from_probe();
     // with overwrite mode
     opts.overwrite_existing = true;
@@ -688,10 +689,11 @@ fn probe_gitoxide_dir() -> crate::Result<gix_fs::Capabilities> {
 fn opts_from_probe() -> gix_worktree_state::checkout::Options {
     static CAPABILITIES: Lazy<gix_fs::Capabilities> = Lazy::new(|| probe_gitoxide_dir().unwrap());
 
+    // FIXME(integration): Restore multithreaded `thread_limit` prior to merging #2008.
     gix_worktree_state::checkout::Options {
         fs: *CAPABILITIES,
         destination_is_initially_empty: true,
-        thread_limit: gix_features::parallel::num_threads(None).into(),
+        thread_limit: Some(1), // gix_features::parallel::num_threads(None).into(),
         ..Default::default()
     }
 }