Move test kernels to a separate workspace

The test kernels need to be built for a different target and we don't want to unify dependency features with the main packages (as this can lead to enabled `std` features).

.github/workflows/ci.yml

@@ -25,6 +25,9 @@ jobs:
       - uses: r7kamura/[email protected]
       - name: "Run `cargo check`"
         run: cargo check --all-targets --all
+      - name: "Check test kernels"
+        run: cargo check --all
+        working-directory: tests/test_kernels
       - name: "Check docs.rs build"
         run: cargo check
         env:
@@ -89,6 +92,8 @@ jobs:
       - uses: actions/checkout@v3
       - uses: r7kamura/[email protected]
       - run: cargo fmt --all -- --check
+      - run: cargo fmt --all -- --check
+        working-directory: tests/test_kernels
 
   clippy:
     name: Clippy
@@ -99,6 +104,8 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - uses: r7kamura/[email protected]
       - run: cargo clippy --all --all-targets
+      - run: cargo clippy --all
+        working-directory: tests/test_kernels
 
   semver-checks:
     name: Semver Checks

Cargo.toml

@@ -19,17 +19,8 @@ members = [
     "bios/stage-*",
     "bios/common",
     "tests/runner",
-    "tests/test_kernels/default_settings",
-    "tests/test_kernels/map_phys_mem",
-    "tests/test_kernels/higher_half",
-    "tests/test_kernels/pie",
-    "tests/test_kernels/lto",
-    "tests/test_kernels/ramdisk",
-    "tests/test_kernels/min_stack",
-    "tests/test_kernels/lower_memory_free",
-    "tests/test_kernels/write_usable_memory",
 ]
-exclude = ["examples/basic", "examples/test_framework"]
+exclude = ["examples/basic", "examples/test_framework", "tests/test_kernels"]
 
 [workspace.package]
 # don't forget to update `workspace.dependencies` below

tests/test_kernels/.cargo/config.toml

@@ -1,2 +1,3 @@
 [build]
 target-dir = "../../target"
+target = "x86_64-unknown-none"

tests/test_kernels/Cargo.toml

@@ -0,0 +1,13 @@
+[workspace]
+resolver = "2"
+members = [
+    "default_settings",
+    "map_phys_mem",
+    "higher_half",
+    "pie",
+    "lto",
+    "ramdisk",
+    "min_stack",
+    "lower_memory_free",
+    "write_usable_memory",
+]