Replace integration test with unit test

Library/Homebrew/test/dev-cmd/test_spec.rb

@@ -17,40 +17,4 @@ describe "brew test" do
       .and not_to_output.to_stderr
       .and be_a_success
   end
-
-  describe "using inreplace" do
-    it "replaces text in file", :integration_test do
-      install_test_formula "testball", <<~RUBY
-        test do
-          (testpath/"file.txt").write "1"
-          inreplace testpath/"file.txt" do |s|
-            s.gsub! "1", "2"
-          end
-          assert_equal "2", (testpath/"file.txt").read
-        end
-      RUBY
-
-      expect { brew "test", "--verbose", "testball" }
-        .to output(/Testing testball/).to_stdout
-        .and not_to_output.to_stderr
-        .and be_a_success
-    end
-
-    it "fails when assertion fails", :integration_test do
-      install_test_formula "testball", <<~RUBY
-        test do
-          (testpath/"file.txt").write "1"
-          inreplace testpath/"file.txt" do |s|
-            s.gsub! "1", "2"
-          end
-          assert_equal "3", (testpath/"file.txt").read
-        end
-      RUBY
-
-      expect { brew "test", "--verbose", "testball" }
-        .to output(/Testing testball/).to_stdout
-        .and output(/Expected: "3"\n  Actual: "2"/).to_stderr
-        .and be_a_failure
-    end
-  end
 end

Library/Homebrew/test/formula_spec.rb

@@ -464,6 +464,26 @@ describe Formula do
 
       expect { f.inreplace([]) }.to raise_error(BuildError)
     end
+
+    specify "replaces text in file" do
+      file = Tempfile.new("test")
+      File.binwrite(file, <<~EOS)
+        ab
+        bc
+        cd
+      EOS
+      f = formula do
+        url "https://brew.sh/test-1.0.tbz"
+      end
+      f.inreplace(file.path) do |s|
+        s.gsub!("bc", "yz")
+      end
+      expect(File.binread(file)).to eq <<~EOS
+        ab
+        yz
+        cd
+      EOS
+    end
   end
 
   describe "::installed_with_alias_path" do