diff --git a/Library/Homebrew/dev-cmd/determine-test-runners.rb b/Library/Homebrew/dev-cmd/determine-test-runners.rb
index a21cf98c98..8dac2d9e0d 100755
--- a/Library/Homebrew/dev-cmd/determine-test-runners.rb
+++ b/Library/Homebrew/dev-cmd/determine-test-runners.rb
@@ -2,118 +2,7 @@
 # frozen_string_literal: true
 
 require "cli/parser"
-require "formula"
-
-class TestRunnerFormula
-  extend T::Sig
-
-  sig { returns(String) }
-  attr_reader :name
-
-  sig { returns(Formula) }
-  attr_reader :formula
-
-  sig { returns(T::Boolean) }
-  attr_reader :eval_all
-
-  sig { params(formula: Formula, eval_all: T::Boolean).void }
-  def initialize(formula, eval_all: Homebrew::EnvConfig.eval_all?)
-    @formula = T.let(formula, Formula)
-    @name = T.let(formula.name, String)
-    @dependent_hash = T.let({}, T::Hash[Symbol, T::Array[TestRunnerFormula]])
-    @eval_all = T.let(eval_all, T::Boolean)
-    freeze
-  end
-
-  sig { returns(T::Boolean) }
-  def macos_only?
-    formula.requirements.any? { |r| r.is_a?(MacOSRequirement) && !r.version_specified? }
-  end
-
-  sig { returns(T::Boolean) }
-  def macos_compatible?
-    !linux_only?
-  end
-
-  sig { returns(T::Boolean) }
-  def linux_only?
-    formula.requirements.any?(LinuxRequirement)
-  end
-
-  sig { returns(T::Boolean) }
-  def linux_compatible?
-    !macos_only?
-  end
-
-  sig { returns(T::Boolean) }
-  def x86_64_only?
-    formula.requirements.any? { |r| r.is_a?(ArchRequirement) && (r.arch == :x86_64) }
-  end
-
-  sig { returns(T::Boolean) }
-  def x86_64_compatible?
-    !arm64_only?
-  end
-
-  sig { returns(T::Boolean) }
-  def arm64_only?
-    formula.requirements.any? { |r| r.is_a?(ArchRequirement) && (r.arch == :arm64) }
-  end
-
-  sig { returns(T::Boolean) }
-  def arm64_compatible?
-    !x86_64_only?
-  end
-
-  sig { returns(T.nilable(MacOSRequirement)) }
-  def versioned_macos_requirement
-    formula.requirements.find { |r| r.is_a?(MacOSRequirement) && r.version_specified? }
-  end
-
-  sig { params(macos_version: OS::Mac::Version).returns(T::Boolean) }
-  def compatible_with?(macos_version)
-    # Assign to a variable to assist type-checking.
-    requirement = versioned_macos_requirement
-    return true if requirement.blank?
-
-    macos_version.public_send(requirement.comparator, requirement.version)
-  end
-
-  SIMULATE_SYSTEM_SYMBOLS = T.let({ arm64: :arm, x86_64: :intel }.freeze, T::Hash[Symbol, Symbol])
-
-  sig {
-    params(
-      platform:      Symbol,
-      arch:          Symbol,
-      macos_version: T.nilable(Symbol),
-    ).returns(T::Array[TestRunnerFormula])
-  }
-  def dependents(platform:, arch:, macos_version:)
-    cache_key = :"#{platform}_#{arch}_#{macos_version}"
-
-    @dependent_hash.fetch(cache_key) do
-      all = eval_all || Homebrew::EnvConfig.eval_all?
-      formula_selector, eval_all_env = if all
-        [:all, "1"]
-      else
-        [:installed, nil]
-      end
-
-      with_env(HOMEBREW_EVAL_ALL: eval_all_env) do
-        Formulary.clear_cache
-        Homebrew::SimulateSystem.arch = SIMULATE_SYSTEM_SYMBOLS.fetch(arch)
-        Homebrew::SimulateSystem.os = macos_version || platform
-
-        Formula.send(formula_selector)
-               .select { |candidate_f| candidate_f.deps.map(&:name).include?(name) }
-               .map { |f| TestRunnerFormula.new(f, eval_all: all) }
-               .freeze
-      ensure
-        Homebrew::SimulateSystem.clear
-      end
-    end
-  end
-end
+require "test_runner_formula"
 
 module Homebrew
   extend T::Sig
diff --git a/Library/Homebrew/test_runner_formula.rb b/Library/Homebrew/test_runner_formula.rb
new file mode 100644
index 0000000000..215af2eee6
--- /dev/null
+++ b/Library/Homebrew/test_runner_formula.rb
@@ -0,0 +1,115 @@
+# typed: strict
+# frozen_string_literal: true
+
+require "formula"
+
+class TestRunnerFormula
+  extend T::Sig
+
+  sig { returns(String) }
+  attr_reader :name
+
+  sig { returns(Formula) }
+  attr_reader :formula
+
+  sig { returns(T::Boolean) }
+  attr_reader :eval_all
+
+  sig { params(formula: Formula, eval_all: T::Boolean).void }
+  def initialize(formula, eval_all: Homebrew::EnvConfig.eval_all?)
+    @formula = T.let(formula, Formula)
+    @name = T.let(formula.name, String)
+    @dependent_hash = T.let({}, T::Hash[Symbol, T::Array[TestRunnerFormula]])
+    @eval_all = T.let(eval_all, T::Boolean)
+    freeze
+  end
+
+  sig { returns(T::Boolean) }
+  def macos_only?
+    formula.requirements.any? { |r| r.is_a?(MacOSRequirement) && !r.version_specified? }
+  end
+
+  sig { returns(T::Boolean) }
+  def macos_compatible?
+    !linux_only?
+  end
+
+  sig { returns(T::Boolean) }
+  def linux_only?
+    formula.requirements.any?(LinuxRequirement)
+  end
+
+  sig { returns(T::Boolean) }
+  def linux_compatible?
+    !macos_only?
+  end
+
+  sig { returns(T::Boolean) }
+  def x86_64_only?
+    formula.requirements.any? { |r| r.is_a?(ArchRequirement) && (r.arch == :x86_64) }
+  end
+
+  sig { returns(T::Boolean) }
+  def x86_64_compatible?
+    !arm64_only?
+  end
+
+  sig { returns(T::Boolean) }
+  def arm64_only?
+    formula.requirements.any? { |r| r.is_a?(ArchRequirement) && (r.arch == :arm64) }
+  end
+
+  sig { returns(T::Boolean) }
+  def arm64_compatible?
+    !x86_64_only?
+  end
+
+  sig { returns(T.nilable(MacOSRequirement)) }
+  def versioned_macos_requirement
+    formula.requirements.find { |r| r.is_a?(MacOSRequirement) && r.version_specified? }
+  end
+
+  sig { params(macos_version: OS::Mac::Version).returns(T::Boolean) }
+  def compatible_with?(macos_version)
+    # Assign to a variable to assist type-checking.
+    requirement = versioned_macos_requirement
+    return true if requirement.blank?
+
+    macos_version.public_send(requirement.comparator, requirement.version)
+  end
+
+  SIMULATE_SYSTEM_SYMBOLS = T.let({ arm64: :arm, x86_64: :intel }.freeze, T::Hash[Symbol, Symbol])
+
+  sig {
+    params(
+      platform:      Symbol,
+      arch:          Symbol,
+      macos_version: T.nilable(Symbol),
+    ).returns(T::Array[TestRunnerFormula])
+  }
+  def dependents(platform:, arch:, macos_version:)
+    cache_key = :"#{platform}_#{arch}_#{macos_version}"
+
+    @dependent_hash.fetch(cache_key) do
+      all = eval_all || Homebrew::EnvConfig.eval_all?
+      formula_selector, eval_all_env = if all
+        [:all, "1"]
+      else
+        [:installed, nil]
+      end
+
+      with_env(HOMEBREW_EVAL_ALL: eval_all_env) do
+        Formulary.clear_cache
+        Homebrew::SimulateSystem.arch = SIMULATE_SYSTEM_SYMBOLS.fetch(arch)
+        Homebrew::SimulateSystem.os = macos_version || platform
+
+        Formula.send(formula_selector)
+               .select { |candidate_f| candidate_f.deps.map(&:name).include?(name) }
+               .map { |f| TestRunnerFormula.new(f, eval_all: all) }
+               .freeze
+      ensure
+        Homebrew::SimulateSystem.clear
+      end
+    end
+  end
+end