diff --git a/Library/Homebrew/test/cmd/install_spec.rb b/Library/Homebrew/test/cmd/install_spec.rb
index e5b5ec63127a2d0e51d5b7e43071d8ba47fb5495..c1240a30e0a5c7f42c53a7e86e515d0f4927e249 100644
--- a/Library/Homebrew/test/cmd/install_spec.rb
+++ b/Library/Homebrew/test/cmd/install_spec.rb
@@ -19,7 +19,7 @@ describe "brew install", :integration_test do
 
     expect { brew "install", "testball1" }
       .to output(%r{#{HOMEBREW_CELLAR}/testball1/0\.1}).to_stdout
-      .and output(/not in your PATH/).to_stderr
+      .and not_to_output.to_stderr
       .and be_a_success
 
     expect { brew "install", "testball1" }
@@ -62,7 +62,7 @@ describe "brew install", :integration_test do
 
     expect { brew "install", "testball1" }
       .to output(%r{#{HOMEBREW_CELLAR}/testball1/1\.0}).to_stdout
-      .and output(/not in your PATH/).to_stderr
+      .and not_to_output.to_stderr
       .and be_a_success
 
     FileUtils.rm path
@@ -88,7 +88,7 @@ describe "brew install", :integration_test do
 
     expect { brew "install", "testball1", "--devel" }
       .to output(%r{#{HOMEBREW_CELLAR}/testball1/3\.0}).to_stdout
-      .and output(/not in your PATH/).to_stderr
+      .and not_to_output.to_stderr
       .and be_a_success
 
     expect { brew "unlink", "testball1" }
@@ -98,7 +98,7 @@ describe "brew install", :integration_test do
 
     expect { brew "install", "testball1" }
       .to output(%r{#{HOMEBREW_CELLAR}/testball1/2\.0}).to_stdout
-      .and output(/not in your PATH/).to_stderr
+      .and not_to_output.to_stderr
       .and be_a_success
 
     shutup do
@@ -181,7 +181,7 @@ describe "brew install", :integration_test do
     # formula since we only have testball1 formula.
     expect { brew "install", "testball1", "--HEAD", "--ignore-dependencies" }
       .to output(%r{#{HOMEBREW_CELLAR}/testball1/HEAD\-d5eb689}).to_stdout
-      .and output(/not in your PATH/).to_stderr
+      .and output(/Cloning into/).to_stderr
       .and be_a_success
 
     expect { brew "install", "testball1", "--HEAD", "--ignore-dependencies" }
@@ -196,7 +196,7 @@ describe "brew install", :integration_test do
 
     expect { brew "install", "testball1" }
       .to output(%r{#{HOMEBREW_CELLAR}/testball1/1\.0}).to_stdout
-      .and output(/not in your PATH/).to_stderr
+      .and not_to_output.to_stderr
       .and be_a_success
   end
 
@@ -220,7 +220,7 @@ describe "brew install", :integration_test do
     # FIXME: This should output to STDERR.
     expect { brew "install", "testball1" }
       .to output(/NonFatalRequirement unsatisfied!/).to_stdout
-      .and output(/not in your PATH/).to_stderr
+      .and not_to_output.to_stderr
       .and be_a_success
   end
 
diff --git a/Library/Homebrew/test/cmd/reinstall_spec.rb b/Library/Homebrew/test/cmd/reinstall_spec.rb
index 74d36bbb81b22c46d87596536640ca61d6514e6a..63584e6be67cec05415c1e202e9445e60a5e556d 100644
--- a/Library/Homebrew/test/cmd/reinstall_spec.rb
+++ b/Library/Homebrew/test/cmd/reinstall_spec.rb
@@ -1,9 +1,6 @@
 require "extend/ENV"
 
 describe "brew reinstall", :integration_test do
-  let(:bin) { (HOMEBREW_PREFIX/"bin").realpath }
-  let(:path) { "#{bin}#{File::PATH_SEPARATOR}#{ENV["PATH"]}" }
-
   before(:each) do
     setup_test_formula "testball"
 
@@ -17,7 +14,7 @@ describe "brew reinstall", :integration_test do
     expect(foo_dir).to exist
     foo_dir.rmtree
 
-    expect { brew "reinstall", "testball", "PATH" => path }
+    expect { brew "reinstall", "testball" }
       .to output(/Reinstalling testball --with-foo/).to_stdout
       .and not_to_output.to_stderr
       .and be_a_success
@@ -26,7 +23,7 @@ describe "brew reinstall", :integration_test do
   end
 
   it "reinstalls a Formula even when one of the options is invalid" do
-    expect { brew "reinstall", "testball", "--with-fo", "PATH" => path }
+    expect { brew "reinstall", "testball", "--with-fo" }
       .to output(/Reinstalling testball --with-foo/).to_stdout
       .and output(/testball: this formula has no \-\-with-fo option so it will be ignored!/).to_stderr
       .and be_a_success
diff --git a/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb b/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
index fc7b49fa4de837a1518eafb334f908d1861c8f91..2eb98826aa5c8521ec82ddec0737438c6b77b40f 100644
--- a/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
+++ b/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
@@ -63,7 +63,15 @@ RSpec.shared_context "integration test" do
   def brew(*args)
     env = args.last.is_a?(Hash) ? args.pop : {}
 
+    # Avoid warnings when HOMEBREW_PREFIX/bin is not in PATH.
+    path = [
+      env["PATH"],
+      (HOMEBREW_PREFIX/"bin").realpath.to_s,
+      ENV["PATH"],
+    ].compact.join(File::PATH_SEPARATOR)
+
     env.merge!(
+      "PATH" => path,
       "HOMEBREW_BREW_FILE" => HOMEBREW_PREFIX/"bin/brew",
       "HOMEBREW_INTEGRATION_TEST" => command_id_from_args(args),
       "HOMEBREW_TEST_TMPDIR" => TEST_TMPDIR,