Add FreeBSD Platform Detection

src/Cake.Common.Tests/Unit/EnvironmentAliasesTests.cs

@@ -182,6 +182,7 @@ public void Should_Throw_If_Context_Is_Null()
             [Theory]
             [InlineData(PlatformFamily.Linux, false)]
             [InlineData(PlatformFamily.OSX, false)]
+            [InlineData(PlatformFamily.FreeBSD, false)]
             [InlineData(PlatformFamily.Windows, true)]
             public void Should_Return_Correct_Value(PlatformFamily family, bool expected)
             {
@@ -212,6 +213,7 @@ public void Should_Throw_If_Context_Is_Null()
             [Theory]
             [InlineData(PlatformFamily.Linux, true)]
             [InlineData(PlatformFamily.OSX, true)]
+            [InlineData(PlatformFamily.FreeBSD, true)]
             [InlineData(PlatformFamily.Windows, false)]
             public void Should_Return_Correct_Value(PlatformFamily family, bool expected)
             {
@@ -242,6 +244,7 @@ public void Should_Throw_If_Context_Is_Null()
             [Theory]
             [InlineData(PlatformFamily.Linux, true)]
             [InlineData(PlatformFamily.OSX, false)]
+            [InlineData(PlatformFamily.FreeBSD, false)]
             [InlineData(PlatformFamily.Windows, false)]
             public void Should_Return_Correct_Value(PlatformFamily family, bool expected)
             {
@@ -272,6 +275,7 @@ public void Should_Throw_If_Context_Is_Null()
             [Theory]
             [InlineData(PlatformFamily.Linux, false)]
             [InlineData(PlatformFamily.OSX, true)]
+            [InlineData(PlatformFamily.FreeBSD, false)]
             [InlineData(PlatformFamily.Windows, false)]
             public void Should_Return_Correct_Value(PlatformFamily family, bool expected)
             {
@@ -286,5 +290,36 @@ public void Should_Return_Correct_Value(PlatformFamily family, bool expected)
                 Assert.Equal(expected, result);
             }
         }
+
+        public sealed class TheIsRunningOnFreeBSDMethod
+        {
+            [Fact]
+            public void Should_Throw_If_Context_Is_Null()
+            {
+                // Given, When
+                var result = Record.Exception(() => EnvironmentAliases.IsRunningOnFreeBSD(null));
+
+                // Then
+                AssertEx.IsArgumentNullException(result, "context");
+            }
+
+            [Theory]
+            [InlineData(PlatformFamily.Linux, false)]
+            [InlineData(PlatformFamily.OSX, false)]
+            [InlineData(PlatformFamily.FreeBSD, true)]
+            [InlineData(PlatformFamily.Windows, false)]
+            public void Should_Return_Correct_Value(PlatformFamily family, bool expected)
+            {
+                // Given
+                var context = Substitute.For<ICakeContext>();
+                context.Environment.Returns(new FakeEnvironment(family));
+
+                // When
+                var result = EnvironmentAliases.IsRunningOnFreeBSD(context);
+
+                // Then
+                Assert.Equal(expected, result);
+            }
+        }
     }
 }

src/Cake.Common/EnviromentAliases.cs

@@ -216,6 +216,32 @@ public static bool IsRunningOnMacOs(this ICakeContext context)
             return context.Environment.Platform.IsOSX();
         }
 
+        /// <summary>
+        /// Determines whether the build script running on a FreeBSD based system.
+        /// </summary>
+        /// <example>
+        /// <code>
+        /// if (IsRunningOnFreeBSD())
+        /// {
+        ///     Information("FreeBSD!");
+        /// }
+        /// </code>
+        /// </example>
+        /// <param name="context">The context.</param>
+        /// <returns>
+        ///   <c>true</c> if the build script running on a FreeBSD based system; otherwise <c>false</c>.
+        /// </returns>
+        [CakeMethodAlias]
+        [CakeAliasCategory("Platform")]
+        public static bool IsRunningOnFreeBSD(this ICakeContext context)
+        {
+            if (context is null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+            return context.Environment.Platform.IsFreeBSD();
+        }
+
         /// <summary>
         /// Determines whether the build script running on a Linux based system.
         /// </summary>

src/Cake.Common/Tools/MSBuild/MSBuildResolver.cs

@@ -41,6 +41,17 @@ public static FilePath GetMSBuildPath(IFileSystem fileSystem, ICakeEnvironment e
 
                 throw new CakeException("Could not resolve MSBuild.");
             }
+            else if (environment.Platform.Family == PlatformFamily.FreeBSD)
+            {
+                var freebsdMSBuildPath = new FilePath("/usr/local/bin/msbuild");
+
+                if (fileSystem.Exist(freebsdMSBuildPath))
+                {
+                    return freebsdMSBuildPath;
+                }
+
+                throw new CakeException("Could not resolve MSBuild.");
+            }
 
             var binPath = settings.ToolVersion == MSBuildToolVersion.Default
                 ? GetHighestAvailableMSBuildVersion(fileSystem, environment, buildPlatform, settings.AllowPreviewVersion)

src/Cake.Core/Extensions/CakePlatformExtensions.cs

@@ -68,5 +68,19 @@ public static bool IsLinux(this ICakePlatform platform)
             }
             return EnvironmentHelper.IsLinux(platform.Family);
         }
+
+        /// <summary>
+        /// Determines whether the specified platform is a FreeBSD platform.
+        /// </summary>
+        /// <param name="platform">The platform.</param>
+        /// <returns><c>true</c> if the platform is a FreeBSD platform; otherwise <c>false</c>.</returns>
+        public static bool IsFreeBSD(this ICakePlatform platform)
+        {
+            if (platform is null)
+            {
+                throw new ArgumentNullException(nameof(platform));
+            }
+            return EnvironmentHelper.IsFreeBSD(platform.Family);
+        }
     }
 }

src/Cake.Core/PlatformFamily.cs

@@ -28,6 +28,11 @@ public enum PlatformFamily
         /// Represents the OSX platform family.
         /// </summary>
         // ReSharper disable once InconsistentNaming
-        OSX = 3
+        OSX = 3,
+
+        /// <summary>
+        /// Represents the FreeBSD platform family.
+        /// </summary>
+        FreeBSD = 4,
     }
 }

src/Cake.Core/Polyfill/EnvironmentHelper.cs

@@ -54,6 +54,16 @@ public static PlatformFamily GetPlatformFamily()
             catch (PlatformNotSupportedException)
             {
             }
+            try
+            {
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.Create("FREEBSD")))
+                {
+                    return PlatformFamily.FreeBSD;
+                }
+            }
+            catch (PlatformNotSupportedException)
+            {
+            }
 
             return PlatformFamily.Unknown;
         }
@@ -81,7 +91,8 @@ public static bool IsUnix()
         public static bool IsUnix(PlatformFamily family)
         {
             return family == PlatformFamily.Linux
-                   || family == PlatformFamily.OSX;
+                   || family == PlatformFamily.OSX
+                   || family == PlatformFamily.FreeBSD;
         }
 
         public static bool IsOSX(PlatformFamily family)
@@ -94,6 +105,11 @@ public static bool IsLinux(PlatformFamily family)
             return family == PlatformFamily.Linux;
         }
 
+        public static bool IsFreeBSD(PlatformFamily family)
+        {
+            return family == PlatformFamily.FreeBSD;
+        }
+
         public static Runtime GetRuntime()
         {
             if (IsCoreClr())