diff --git a/.bazelci/postsubmit.yml b/.bazelci/postsubmit.yml
index 67f4a9ac43699a..ddb47ab1f8494d 100644
--- a/.bazelci/postsubmit.yml
+++ b/.bazelci/postsubmit.yml
@@ -222,12 +222,6 @@ tasks:
       - "-//src/test/shell/bazel/android:android_instrumentation_test_integration_test_with_head_android_tools"
       - "-//src/test/shell/bazel/android:aapt_integration_test"
       - "-//src/test/shell/bazel/android:aapt_integration_test_with_head_android_tools"
-      # Disable recently regressed tests: https://github.com/bazelbuild/bazel/issues/20437
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CppSysrootTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CcImportConfiguredTargetTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/objc:ObjcRulesTests"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/objc:BazelJ2ObjcLibraryTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CcToolchainTest"
     include_json_profile:
       - build
       - test
@@ -288,12 +282,6 @@ tasks:
       - "-//src/test/shell/bazel/android:android_instrumentation_test_integration_test_with_head_android_tools"
       - "-//src/test/shell/bazel/android:aapt_integration_test"
       - "-//src/test/shell/bazel/android:aapt_integration_test_with_head_android_tools"
-      # Disable recently regressed tests: https://github.com/bazelbuild/bazel/issues/20437
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CppSysrootTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CcImportConfiguredTargetTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/objc:ObjcRulesTests"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/objc:BazelJ2ObjcLibraryTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CcToolchainTest"
       # https://github.com/bazelbuild/bazel/issues/17411
       - "-//src/test/java/com/google/devtools/build/lib/blackbox/tests/workspace:PatchApiBlackBoxTest"
       # https://github.com/bazelbuild/bazel/issues/17447
diff --git a/.bazelci/presubmit.yml b/.bazelci/presubmit.yml
index c474d1c9710d7a..a2f32dffa84885 100644
--- a/.bazelci/presubmit.yml
+++ b/.bazelci/presubmit.yml
@@ -226,12 +226,6 @@ tasks:
       - "-//src/test/shell/bazel/android:android_instrumentation_test_integration_test_with_head_android_tools"
       - "-//src/test/shell/bazel/android:aapt_integration_test"
       - "-//src/test/shell/bazel/android:aapt_integration_test_with_head_android_tools"
-      # Disable recently regressed tests: https://github.com/bazelbuild/bazel/issues/20437
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CppSysrootTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CcImportConfiguredTargetTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/objc:ObjcRulesTests"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/objc:BazelJ2ObjcLibraryTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CcToolchainTest"
     include_json_profile:
       - build
       - test
@@ -346,13 +340,6 @@ tasks:
       - "-//src/test/shell/bazel/android:android_instrumentation_test_integration_test_with_head_android_tools"
       - "-//src/test/shell/bazel/android:aapt_integration_test"
       - "-//src/test/shell/bazel/android:aapt_integration_test_with_head_android_tools"
-      # Disable recently regressed tests: https://github.com/bazelbuild/bazel/issues/20437
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CppSysrootTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CcImportConfiguredTargetTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/objc:ObjcRulesTests"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/objc:BazelJ2ObjcLibraryTest"
-      - "-//src/test/java/com/google/devtools/build/lib/rules/cpp:CcToolchainTest"
-      - "-//src/test/shell/integration:minimal_jdk_test"
       # https://github.com/bazelbuild/bazel/issues/17411
       - "-//src/test/java/com/google/devtools/build/lib/blackbox/tests/workspace:PatchApiBlackBoxTest"
       # https://github.com/bazelbuild/bazel/issues/17447
diff --git a/src/test/java/com/google/devtools/build/lib/packages/util/Crosstool.java b/src/test/java/com/google/devtools/build/lib/packages/util/Crosstool.java
index 841d0f058bebd7..5bf080dcf6378b 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/util/Crosstool.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/util/Crosstool.java
@@ -301,12 +301,24 @@ public String getToolchainExecConstraints() {
 
     public String getToolchainTargetConstraints() {
       ImmutableList<String> constraints = this.toolchainTargetConstraints;
-      if (constraints.isEmpty() && getTargetCpu().equals("k8")) {
-        // Use default constraints
-        constraints =
-            ImmutableList.of(
-                TestConstants.CONSTRAINTS_PACKAGE_ROOT + "cpu:x86_64",
-                TestConstants.CONSTRAINTS_PACKAGE_ROOT + "os:linux");
+      if (constraints.isEmpty()) {
+        if (getTargetCpu().equals("k8")) {
+          // Use default constraints
+          constraints =
+              ImmutableList.of(
+                  TestConstants.CONSTRAINTS_PACKAGE_ROOT + "cpu:x86_64",
+                  TestConstants.CONSTRAINTS_PACKAGE_ROOT + "os:linux");
+        } else if (getTargetCpu().equals("darwin_x86_64")) {
+          constraints =
+              ImmutableList.of(
+                  TestConstants.CONSTRAINTS_PACKAGE_ROOT + "cpu:x86_64",
+                  TestConstants.CONSTRAINTS_PACKAGE_ROOT + "os:macos");
+        } else if (getTargetCpu().equals("darwin_arm64")) {
+          constraints =
+              ImmutableList.of(
+                  TestConstants.CONSTRAINTS_PACKAGE_ROOT + "cpu:arm64",
+                  TestConstants.CONSTRAINTS_PACKAGE_ROOT + "os:macos");
+        }
       }
       return formatConstraints("target", constraints);
     }
@@ -727,15 +739,14 @@ public void writeOSX() throws IOException {
           "    toolchain_type = '" + TestConstants.TOOLS_REPOSITORY + "//tools/cpp:toolchain_type'",
           ")");
       crosstoolBuild.add(toolchainConfig.getCcToolchainConfigRule());
-      // Add the newly-created toolchain to the WORKSPACE.
-      config.append(
-          "WORKSPACE",
-          "register_toolchains('//" + MockObjcSupport.DEFAULT_OSX_CROSSTOOL_DIR + ":all')");
     }
 
     config.overwrite(
         MockObjcSupport.DEFAULT_OSX_CROSSTOOL_DIR + "/BUILD",
         Joiner.on("\n").join(crosstoolBuild.build()));
+    config.append(
+        "WORKSPACE",
+        "register_toolchains('//" + MockObjcSupport.DEFAULT_OSX_CROSSTOOL_DIR + ":all')");
     config.overwrite(crosstoolTop + "/cc_toolchain_config.bzl", ccToolchainConfigFileContents);
   }
 }
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/BUILD b/src/test/java/com/google/devtools/build/lib/rules/cpp/BUILD
index 15459e8ec20e43..18e7e91f87759d 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/BUILD
@@ -175,12 +175,12 @@ java_test(
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/collect/nestedset",
         "//src/main/java/com/google/devtools/build/lib/rules/cpp",
-        "//src/main/java/com/google/devtools/build/lib/util:os",
         "//src/main/java/com/google/devtools/build/lib/vfs",
         "//src/main/java/com/google/devtools/build/lib/vfs:pathfragment",
         "//src/test/java/com/google/devtools/build/lib/actions/util",
         "//src/test/java/com/google/devtools/build/lib/analysis/util",
         "//src/test/java/com/google/devtools/build/lib/packages:testutil",
+        "//src/test/java/com/google/devtools/build/lib/testutil:TestConstants",
         "//third_party:guava",
         "//third_party:junit4",
         "//third_party:truth",
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/CcCommonTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/CcCommonTest.java
index cc9983c4973ece..9d811b5fbfb08e 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/CcCommonTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/CcCommonTest.java
@@ -37,6 +37,7 @@
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.packages.util.Crosstool.CcToolchainConfig;
 import com.google.devtools.build.lib.packages.util.MockCcSupport;
+import com.google.devtools.build.lib.testutil.TestConstants;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.ModifiedFileSet;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -710,7 +711,17 @@ public void testExpandLabelInLinkoptsAgainstSrc() throws Exception {
   @Test
   public void testCcLibraryWithDashStaticOnDarwin() throws Exception {
     getAnalysisMock().ccSupport().setupCcToolchainConfigForCpu(mockToolsConfig, "darwin_x86_64");
-    useConfiguration("--cpu=darwin_x86_64");
+    mockToolsConfig.create(
+        "platforms/BUILD",
+        "platform(",
+        "  name = 'darwin_x86_64',",
+        "  constraint_values = [",
+        "    '" + TestConstants.CONSTRAINTS_PACKAGE_ROOT + "os:macos',",
+        "    '" + TestConstants.CONSTRAINTS_PACKAGE_ROOT + "cpu:x86_64',",
+        "  ],",
+        ")");
+    useConfiguration("--cpu=darwin_x86_64", "--platforms=//platforms:darwin_x86_64");
+
     checkError(
         "badlib",
         "lib_with_dash_static",
diff --git a/src/test/java/com/google/devtools/build/lib/rules/python/PyTestConfiguredTargetTest.java b/src/test/java/com/google/devtools/build/lib/rules/python/PyTestConfiguredTargetTest.java
index bb277f0c1d792d..f7e32a8894c29f 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/python/PyTestConfiguredTargetTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/python/PyTestConfiguredTargetTest.java
@@ -36,14 +36,15 @@ public void macRequiresDarwinForExecution() throws Exception {
     // The default mock environment doesn't have platform_mappings (which map --cpu to a platform),
     // nor does it have Apple platforms defined, so we have to set one up ourselves.
     mockToolsConfig.create(
-        "mockplatforms/BUILD",
+        "platforms/BUILD",
         "platform(",
-        "    name='macos',",
-        String.format(
-            "    constraint_values=['%sos:macos'],", TestConstants.CONSTRAINTS_PACKAGE_ROOT),
-        ")",
-        "");
-    useConfiguration("--cpu=darwin_x86_64", "--platforms=//mockplatforms:macos");
+        "  name = 'darwin_x86_64',",
+        "  constraint_values = [",
+        "    '" + TestConstants.CONSTRAINTS_PACKAGE_ROOT + "os:macos',",
+        "    '" + TestConstants.CONSTRAINTS_PACKAGE_ROOT + "cpu:x86_64',",
+        "  ],",
+        ")");
+    useConfiguration("--cpu=darwin_x86_64", "--platforms=//platforms:darwin_x86_64");
     scratch.file(
         "pkg/BUILD", //
         "py_test(",