diff --git a/Library/Homebrew/test/bundle/installer_spec.rb b/Library/Homebrew/test/bundle/installer_spec.rb
index edf2520d10260..318910a429020 100644
--- a/Library/Homebrew/test/bundle/installer_spec.rb
+++ b/Library/Homebrew/test/bundle/installer_spec.rb
@@ -163,9 +163,7 @@
   it "does not trust unqualified `trusted: true` names" do
     trusted_formula_entry = Homebrew::Bundle::Dsl::Entry.new(:brew, "mysql", { trusted: true })
 
-    expect(Homebrew::Trust).not_to receive(:trust!)
-
-    described_class.install!([trusted_formula_entry], quiet: true)
+    expect(Homebrew::Bundle::Trust.entries([trusted_formula_entry])).to be_empty
   end
 
   it "skips fetching formulae from fully qualified untapped taps" do
diff --git a/Library/Homebrew/test/cask/artifact/alt_target_spec.rb b/Library/Homebrew/test/cask/artifact/alt_target_spec.rb
index f660d360f849e..f985177faf696 100644
--- a/Library/Homebrew/test/cask/artifact/alt_target_spec.rb
+++ b/Library/Homebrew/test/cask/artifact/alt_target_spec.rb
@@ -10,15 +10,12 @@
         artifact.install_phase(command: NeverSudoSystemCommand, force: false)
       end
     end
-
     let(:source_path) { cask.staged_path.join("Caffeine.app") }
     let(:target_path) { Pathname(cask.config.appdir).join("AnotherName.app") }
 
-    before do
-      InstallHelper.install_without_artifacts(cask)
-    end
-
     it "installs the given apps using the proper target directory" do
+      source_path.mkpath
+
       expect(source_path).to be_a_directory
       expect(target_path).not_to exist
 
@@ -41,7 +38,7 @@
 
       it "installs the given apps using the proper target directory" do
         appsubdir = cask.staged_path.join("subdir").tap(&:mkpath)
-        FileUtils.mv(source_path, appsubdir)
+        (appsubdir/"Caffeine.app").mkpath
 
         install_phase
 
@@ -51,8 +48,9 @@
     end
 
     it "only uses apps when they are specified" do
+      source_path.mkpath
       staged_app_copy = source_path.sub("Caffeine.app", "Caffeine Deluxe.app")
-      FileUtils.cp_r source_path, staged_app_copy
+      staged_app_copy.mkpath
 
       install_phase
 
@@ -64,6 +62,7 @@
     end
 
     it "avoids clobbering an existing app by moving over it" do
+      source_path.mkpath
       target_path.mkpath
 
       expect { install_phase }
diff --git a/Library/Homebrew/test/cask/artifact/bashcompletion_spec.rb b/Library/Homebrew/test/cask/artifact/bashcompletion_spec.rb
index 566b18bc658ee..57a3ff2baa1f2 100644
--- a/Library/Homebrew/test/cask/artifact/bashcompletion_spec.rb
+++ b/Library/Homebrew/test/cask/artifact/bashcompletion_spec.rb
@@ -19,14 +19,13 @@
     let(:full_source_path) { cask.staged_path.join("test.bash-completion") }
     let(:full_target_path) { cask.config.bash_completion.join("test") }
 
-    before do
-      InstallHelper.install_without_artifacts(cask)
-    end
-
     context "with completion" do
       let(:cask_token) { "with-shellcompletion" }
 
       it "links the completion to the proper directory" do
+        source_path.dirname.mkpath
+        source_path.write ""
+
         install_phase.call
 
         expect(File).to be_identical target_path, source_path
@@ -37,6 +36,9 @@
       let(:cask_token) { "with-shellcompletion-long" }
 
       it "links the completion to the proper directory" do
+        full_source_path.dirname.mkpath
+        full_source_path.write ""
+
         install_phase.call
 
         expect(File).to be_identical full_target_path, full_source_path
diff --git a/Library/Homebrew/test/cask/artifact/fishlcompletion_spec.rb b/Library/Homebrew/test/cask/artifact/fishlcompletion_spec.rb
index aec2aeafb8e29..36454ee647eac 100644
--- a/Library/Homebrew/test/cask/artifact/fishlcompletion_spec.rb
+++ b/Library/Homebrew/test/cask/artifact/fishlcompletion_spec.rb
@@ -19,12 +19,11 @@
     let(:full_source_path) { cask.staged_path.join("test.fish-completion") }
     let(:full_target_path) { cask.config.fish_completion.join("test.fish") }
 
-    before do
-      InstallHelper.install_without_artifacts(cask)
-    end
-
     context "with completion" do
       it "links the completion to the proper directory" do
+        source_path.dirname.mkpath
+        source_path.write ""
+
         install_phase.call
 
         expect(File).to be_identical target_path, source_path
@@ -35,6 +34,9 @@
       let(:cask_token) { "with-shellcompletion-long" }
 
       it "links the completion to the proper directory" do
+        full_source_path.dirname.mkpath
+        full_source_path.write ""
+
         install_phase.call
 
         expect(File).to be_identical full_target_path, full_source_path
diff --git a/Library/Homebrew/test/cask/artifact/uninstall_no_zap_spec.rb b/Library/Homebrew/test/cask/artifact/uninstall_no_zap_spec.rb
index 2550aafd08220..d9d7e5212100e 100644
--- a/Library/Homebrew/test/cask/artifact/uninstall_no_zap_spec.rb
+++ b/Library/Homebrew/test/cask/artifact/uninstall_no_zap_spec.rb
@@ -8,10 +8,6 @@
     cask.artifacts.find { |a| a.is_a?(described_class) }
   end
 
-  before do
-    InstallHelper.install_without_artifacts(cask)
-  end
-
   describe "#uninstall_phase" do
     subject { zap_artifact }
 
diff --git a/Library/Homebrew/test/cask/artifact/zshcompletion_spec.rb b/Library/Homebrew/test/cask/artifact/zshcompletion_spec.rb
index b79a4bd583f5a..a83d8bc195974 100644
--- a/Library/Homebrew/test/cask/artifact/zshcompletion_spec.rb
+++ b/Library/Homebrew/test/cask/artifact/zshcompletion_spec.rb
@@ -19,12 +19,11 @@
     let(:full_source_path) { cask.staged_path.join("test.zsh-completion") }
     let(:full_target_path) { cask.config.zsh_completion.join("_test") }
 
-    before do
-      InstallHelper.install_without_artifacts(cask)
-    end
-
     context "with completion" do
       it "links the completion to the proper directory" do
+        source_path.dirname.mkpath
+        source_path.write ""
+
         install_phase.call
 
         expect(File).to be_identical target_path, source_path
@@ -35,6 +34,9 @@
       let(:cask_token) { "with-shellcompletion-long" }
 
       it "links the completion to the proper directory" do
+        full_source_path.dirname.mkpath
+        full_source_path.write ""
+
         install_phase.call
 
         expect(File).to be_identical full_target_path, full_source_path
diff --git a/Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb b/Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb
index 371f057f7e707..004d467558273 100644
--- a/Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb
+++ b/Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb
@@ -84,10 +84,6 @@
           .and have_attributes(token: api_token)
       end
 
-      it "returns nil for full name with invalid tap" do
-        expect(described_class.try_new("homebrew/foo/#{api_token}")).to be_nil
-      end
-
       context "with core tap migration renames" do
         let(:foo_tap) { Tap.fetch("homebrew", "foo") }
 
@@ -140,10 +136,6 @@
           .and have_attributes(token: internal_api_token)
       end
 
-      it "returns nil for full name with invalid tap" do
-        expect(described_class.try_new("homebrew/foo/#{internal_api_token}")).to be_nil
-      end
-
       context "with core tap migration renames" do
         let(:foo_tap) { Tap.fetch("homebrew", "foo") }
 
@@ -180,6 +172,10 @@
         end
       end
     end
+
+    it "returns nil for full name with invalid tap" do
+      expect(described_class.try_new("homebrew/foo/test-opera")).to be_nil
+    end
   end
 
   describe "#load" do
diff --git a/Library/Homebrew/test/cmd/help_spec.rb b/Library/Homebrew/test/cmd/help_spec.rb
index a81fb776e2465..d428d130eded1 100644
--- a/Library/Homebrew/test/cmd/help_spec.rb
+++ b/Library/Homebrew/test/cmd/help_spec.rb
@@ -104,9 +104,7 @@ def run; end
         .to output(%r{trusthelp/foo}).to_stderr
         .and be_a_failure
 
-      expect { brew "trust", "--command", "trusthelp/foo/hello-trust-tap", trust_env.dup }
-        .to output(%r{Trusted command: trusthelp/foo/hello-trust-tap}).to_stdout
-        .and be_a_success
+      with_env(trust_env) { Homebrew::Trust.trust!(:command, "trusthelp/foo/hello-trust-tap") }
 
       expect { brew "help", "hello-trust-tap", require_trust_env.dup }
         .to output(%r{^From tap: trusthelp/foo$}).to_stdout
diff --git a/Library/Homebrew/test/cmd/reinstall_spec.rb b/Library/Homebrew/test/cmd/reinstall_spec.rb
index 60de489f730a6..82ad3c51c9fdf 100644
--- a/Library/Homebrew/test/cmd/reinstall_spec.rb
+++ b/Library/Homebrew/test/cmd/reinstall_spec.rb
@@ -127,7 +127,7 @@
     cmd.run
   end
 
-  it "reinstalls a Formula", :aggregate_failures, :integration_test do
+  it "reinstalls a Formula", :integration_test do
     formula_name = "testball_bottle"
     formula_prefix = HOMEBREW_CELLAR/formula_name/"0.1"
     formula_bin = formula_prefix/"bin"
@@ -142,21 +142,5 @@
       .and output(/✔︎.*/m).to_stderr
       .and be_a_success
     expect(formula_bin).to exist
-
-    FileUtils.rm_r(formula_bin)
-
-    expect { brew "reinstall", formula_name }
-      .to output(/.*Would reinstall 1 formula:\s*#{formula_name}.*/).to_stdout
-      .and output(/✔︎.*/m).to_stderr
-      .and be_a_success
-    expect(formula_bin).to exist
-
-    FileUtils.rm_r(formula_bin)
-
-    expect { brew "reinstall", formula_name, { "HOMEBREW_FORBIDDEN_FORMULAE" => formula_name } }
-      .to not_to_output(/#{Regexp.escape(formula_prefix)}/o).to_stdout
-      .and output(/#{formula_name} was forbidden/).to_stderr
-      .and be_a_failure
-    expect(formula_bin).not_to exist
   end
 end
diff --git a/Library/Homebrew/test/cmd/tab_spec.rb b/Library/Homebrew/test/cmd/tab_spec.rb
index a538a232416f2..31936b1b6948b 100644
--- a/Library/Homebrew/test/cmd/tab_spec.rb
+++ b/Library/Homebrew/test/cmd/tab_spec.rb
@@ -20,7 +20,7 @@ def cask_installed_on_request?(cask)
 
   it_behaves_like "parseable arguments"
 
-  it "marks or unmarks a formula as installed on request", :integration_test do
+  it "marks a formula as installed on request", :integration_test do
     setup_test_formula "foo",
                        tab_attributes: { "installed_on_request" => false }
     foo = Formula["foo"]
@@ -30,12 +30,6 @@ def cask_installed_on_request?(cask)
       .and output(/foo is now marked as installed on request/).to_stdout
       .and not_to_output.to_stderr
     expect(installed_on_request?(foo)).to be true
-
-    expect { brew "tab", "--no-installed-on-request", "foo" }
-      .to be_a_success
-      .and output(/foo is now marked as not installed on request/).to_stdout
-      .and not_to_output.to_stderr
-    expect(installed_on_request?(foo)).to be false
   end
 
   it "marks or unmarks a cask as installed on request with a missing tab", :cask do
diff --git a/Library/Homebrew/test/cmd/unlink_spec.rb b/Library/Homebrew/test/cmd/unlink_spec.rb
index 87c38fb282341..6455989f1001d 100644
--- a/Library/Homebrew/test/cmd/unlink_spec.rb
+++ b/Library/Homebrew/test/cmd/unlink_spec.rb
@@ -8,7 +8,14 @@
   it_behaves_like "parseable arguments"
 
   it "unlinks a Formula", :integration_test do
-    install_test_formula "testball"
+    setup_test_formula "testball", tab_attributes: { installed_on_request: true }
+    formula_prefix = Formula["testball"].prefix
+    (formula_prefix/"bin").mkpath
+    (formula_prefix/"bin/test").write "test"
+    (HOMEBREW_PREFIX/"bin").mkpath
+    (HOMEBREW_PREFIX/"bin/test").make_relative_symlink(formula_prefix/"bin/test")
+    HOMEBREW_LINKED_KEGS.mkpath
+    (HOMEBREW_LINKED_KEGS/"testball").make_relative_symlink(formula_prefix)
 
     expect { brew "unlink", "testball" }
       .to output(/Unlinking /).to_stdout
diff --git a/Library/Homebrew/test/dev-cmd/test_spec.rb b/Library/Homebrew/test/dev-cmd/test_spec.rb
index f2c161bf91244..0c50bd829c8df 100644
--- a/Library/Homebrew/test/dev-cmd/test_spec.rb
+++ b/Library/Homebrew/test/dev-cmd/test_spec.rb
@@ -9,13 +9,22 @@
   it_behaves_like "parseable arguments"
 
   it "tests a given Formula", :integration_test do
-    with_env(HOMEBREW_NO_INSTALL_FROM_API: "1") do
-      install_test_formula "testball", <<~'RUBY'
-        test do
-          assert_equal "test", shell_output("#{bin}/test")
-        end
-      RUBY
-    end
+    skip "Nested sandboxing is not supported." if Sandbox.nested_sandbox?
+
+    setup_test_formula "testball", <<~'RUBY', tab_attributes: { installed_on_request: true }
+      test do
+        assert_equal "test", shell_output("#{bin}/test")
+      end
+    RUBY
+    formula_prefix = Formula["testball"].prefix
+    (formula_prefix/"bin").mkpath
+    (formula_prefix/"bin/test").write <<~SH
+      #!/bin/sh
+      printf test
+    SH
+    (formula_prefix/"bin/test").chmod 0755
+    HOMEBREW_LINKED_KEGS.mkpath
+    (HOMEBREW_LINKED_KEGS/"testball").make_relative_symlink(formula_prefix)
 
     expect { brew "test", "--verbose", "testball", "HOMEBREW_NO_INSTALL_FROM_API" => "1" }
       .to output(/Testing testball/).to_stdout
@@ -24,19 +33,21 @@
   end
 
   it "blocks network access when test phase is offline", :integration_test do
-    if Sandbox.available?
-      with_env(HOMEBREW_NO_INSTALL_FROM_API: "1") do
-        install_test_formula "testball_offline_test", <<~RUBY
-          deny_network_access! :test
-          test do
-            system "curl", "example.org"
-          end
-        RUBY
+    skip "Sandbox not available." unless Sandbox.available?
+    skip "Nested sandboxing is not supported." if Sandbox.nested_sandbox?
+
+    formula_name = "testball_offline_test"
+    setup_test_formula formula_name, <<~RUBY, tab_attributes: { installed_on_request: true }
+      deny_network_access! :test
+      test do
+        system "curl", "example.org"
       end
+    RUBY
+    HOMEBREW_LINKED_KEGS.mkpath
+    (HOMEBREW_LINKED_KEGS/formula_name).make_relative_symlink(Formula[formula_name].prefix)
 
-      expect { brew "test", "--verbose", "testball_offline_test", "HOMEBREW_NO_INSTALL_FROM_API" => "1" }
-        .to output(/curl: \(6\) Could not resolve host: example\.org/).to_stdout
-        .and be_a_failure
-    end
+    expect { brew "test", "--verbose", formula_name, "HOMEBREW_NO_INSTALL_FROM_API" => "1" }
+      .to output(/curl: \(6\) Could not resolve host: example\.org/).to_stdout
+      .and be_a_failure
   end
 end
diff --git a/Library/Homebrew/test/patching_spec.rb b/Library/Homebrew/test/patching_spec.rb
index 9a34496e2d7a5..9d85790e667a1 100644
--- a/Library/Homebrew/test/patching_spec.rb
+++ b/Library/Homebrew/test/patching_spec.rb
@@ -260,15 +260,19 @@ def formula(name = "formula_name", path: Formulary.core_path(name), spec: :stabl
   end
 
   specify "single_patch_dsl_with_strip_with_apply" do
-    expect(
-      formula do
-        patch :p1 do
-          url "file://#{tarball_fixture("testball-0.1-patches.tgz")}"
-          sha256 tarball_fixture_sha256("testball-0.1-patches.tgz")
-          apply "noop-a.diff"
-        end
-      end,
-    ).to be_patched
+    external_patch = formula do
+      patch :p1 do
+        url "file://#{tarball_fixture("testball-0.1-patches.tgz")}"
+        sha256 tarball_fixture_sha256("testball-0.1-patches.tgz")
+        apply "noop-a.diff"
+      end
+    end.stable.patches.last
+
+    expect(external_patch).to have_attributes(strip: :p1, patch_files: ["noop-a.diff"])
+    external_patch.fetch
+    external_patch.resource.unpack do
+      expect(Pathname.pwd/external_patch.patch_files.fetch(0)).to be_a_file
+    end
   end
 
   specify "single_patch_dsl_with_incorrect_strip" do
diff --git a/Library/Homebrew/test/system_command_spec.rb b/Library/Homebrew/test/system_command_spec.rb
index eee2d1174131c..a331d0ae64d19 100644
--- a/Library/Homebrew/test/system_command_spec.rb
+++ b/Library/Homebrew/test/system_command_spec.rb
@@ -374,17 +374,17 @@
             # Ignore SIGINT.
           end
 
-          described_class.run! "sleep", args: [5]
+          described_class.run! "sleep", args: [1]
 
           exit!
         end
 
-        sleep 1
+        sleep 0.1
         Process.kill("INT", pid)
 
         Process.waitpid(pid)
 
-        expect(Time.now - start_time).to be >= 5
+        expect(Time.now - start_time).to be >= 1
       end
     end
   end