From 30e1a845662b2fb51dbd045dcc749163273b749e Mon Sep 17 00:00:00 2001
From: Brian Clymer <brian.clymer@hudl.com>
Date: Wed, 2 Oct 2019 08:52:22 -0500
Subject: [PATCH 1/6] Working support for scheme templates.

---
 Sources/ProjectSpec/Project.swift             |  11 +-
 Sources/ProjectSpec/Target.swift              |  55 ++++++++-
 Tests/XcodeGenKitTests/SpecLoadingTests.swift | 113 ++++++++++++++++++
 3 files changed, 172 insertions(+), 7 deletions(-)

diff --git a/Sources/ProjectSpec/Project.swift b/Sources/ProjectSpec/Project.swift
index 3e2f1e0d..05905ccb 100644
--- a/Sources/ProjectSpec/Project.swift
+++ b/Sources/ProjectSpec/Project.swift
@@ -153,7 +153,7 @@ extension Project {
     public init(basePath: Path = "", jsonDictionary: JSONDictionary) throws {
         self.basePath = basePath
 
-        let jsonDictionary = try Project.resolveProject(jsonDictionary: jsonDictionary)
+        let jsonDictionary = Project.resolveProject(jsonDictionary: jsonDictionary)
 
         name = try jsonDictionary.json(atKeyPath: "name")
         settings = jsonDictionary.json(atKeyPath: "settings") ?? .empty
@@ -184,14 +184,15 @@ extension Project {
         aggregateTargetsMap = Dictionary(uniqueKeysWithValues: aggregateTargets.map { ($0.name, $0) })
     }
 
-    static func resolveProject(jsonDictionary: JSONDictionary) throws -> JSONDictionary {
+    static func resolveProject(jsonDictionary: JSONDictionary) -> JSONDictionary {
         var jsonDictionary = jsonDictionary
 
         // resolve multiple times so that we support both multi-platform templates,
         // as well as platform specific templates in multi-platform targets
-        jsonDictionary = try Target.resolveMultiplatformTargets(jsonDictionary: jsonDictionary)
-        jsonDictionary = try Target.resolveTargetTemplates(jsonDictionary: jsonDictionary)
-        jsonDictionary = try Target.resolveMultiplatformTargets(jsonDictionary: jsonDictionary)
+        jsonDictionary = Target.resolveMultiplatformTargets(jsonDictionary: jsonDictionary)
+        jsonDictionary = Target.resolveTargetTemplates(jsonDictionary: jsonDictionary)
+        jsonDictionary = Target.resolveSchemeTemplates(jsonDictionary: jsonDictionary)
+        jsonDictionary = Target.resolveMultiplatformTargets(jsonDictionary: jsonDictionary)
 
         return jsonDictionary
     }
diff --git a/Sources/ProjectSpec/Target.swift b/Sources/ProjectSpec/Target.swift
index e305cf40..bcab72ca 100644
--- a/Sources/ProjectSpec/Target.swift
+++ b/Sources/ProjectSpec/Target.swift
@@ -134,7 +134,7 @@ extension Target: PathContainer {
 
 extension Target {
 
-    static func resolveTargetTemplates(jsonDictionary: JSONDictionary) throws -> JSONDictionary {
+    static func resolveTargetTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
         guard var targetsDictionary: [String: JSONDictionary] = jsonDictionary["targets"] as? [String: JSONDictionary] else {
             return jsonDictionary
         }
@@ -186,7 +186,7 @@ extension Target {
         return jsonDictionary
     }
 
-    static func resolveMultiplatformTargets(jsonDictionary: JSONDictionary) throws -> JSONDictionary {
+    static func resolveMultiplatformTargets(jsonDictionary: JSONDictionary) -> JSONDictionary {
         guard let targetsDictionary: [String: JSONDictionary] = jsonDictionary["targets"] as? [String: JSONDictionary] else {
             return jsonDictionary
         }
@@ -236,6 +236,57 @@ extension Target {
         merged["targets"] = crossPlatformTargets
         return merged
     }
+
+    static func resolveSchemeTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
+        guard var schemesDictionary: [String: JSONDictionary] = jsonDictionary["schemes"] as? [String: JSONDictionary] else {
+            return jsonDictionary
+        }
+
+        let schemeTemplatesDictionary: [String: JSONDictionary] = jsonDictionary["schemeTemplates"] as? [String: JSONDictionary] ?? [:]
+
+        // Recursively collects all nested template names of a given dictionary.
+        func collectTemplates(of jsonDictionary: JSONDictionary,
+                              into allTemplates: inout [String],
+                              insertAt insertionIndex: inout Int) {
+            guard let templates = jsonDictionary["templates"] as? [String] else {
+                return
+            }
+            for template in templates where !allTemplates.contains(template) {
+                guard let templateDictionary = schemeTemplatesDictionary[template] else {
+                    continue
+                }
+                allTemplates.insert(template, at: insertionIndex)
+                collectTemplates(of: templateDictionary, into: &allTemplates, insertAt: &insertionIndex)
+                insertionIndex += 1
+            }
+        }
+
+        for (schemeName, var scheme) in schemesDictionary {
+            var templates: [String] = []
+            var index: Int = 0
+            collectTemplates(of: scheme, into: &templates, insertAt: &index)
+            if !templates.isEmpty {
+                var mergedDictionary: JSONDictionary = [:]
+                for template in templates {
+                    if let templateDictionary = schemeTemplatesDictionary[template] {
+                        mergedDictionary = templateDictionary.merged(onto: mergedDictionary)
+                    }
+                }
+                scheme = scheme.merged(onto: mergedDictionary)
+                scheme = scheme.replaceString("${scheme_name}", with: schemeName)
+                if let templateAttributes = scheme["templateAttributes"] as? [String: String] {
+                    for (templateAttribute, value) in templateAttributes {
+                        scheme = scheme.replaceString("${\(templateAttribute)}", with: value)
+                    }
+                }
+            }
+            schemesDictionary[schemeName] = scheme
+        }
+
+        var jsonDictionary = jsonDictionary
+        jsonDictionary["schemes"] = schemesDictionary
+        return jsonDictionary
+    }
 }
 
 extension Target: Equatable {
diff --git a/Tests/XcodeGenKitTests/SpecLoadingTests.swift b/Tests/XcodeGenKitTests/SpecLoadingTests.swift
index 0b80fc2a..94a461e4 100644
--- a/Tests/XcodeGenKitTests/SpecLoadingTests.swift
+++ b/Tests/XcodeGenKitTests/SpecLoadingTests.swift
@@ -853,6 +853,119 @@ class SpecLoadingTests: XCTestCase {
                 try expect(scheme.profile?.environmentVariables.isEmpty) == true
             }
 
+            $0.it("parses scheme templates") {
+                let targetDictionary: [String: Any] = [
+                    "deploymentTarget": "1.2.0",
+                    "sources": ["targetSource"],
+                    "templates": ["temp2", "temp"],
+                    "templateAttributes": [
+                        "source": "replacedSource",
+                    ],
+                ]
+
+                let project = try getProjectSpec([
+                    "targets": ["Framework": targetDictionary],
+                    "targetTemplates": [
+                        "temp": [
+                            "platform": "iOS",
+                            "sources": [
+                                "templateSource",
+                                ["path": "Sources/${target_name}"]
+                            ],
+                        ],
+                        "temp2": [
+                            "type": "framework",
+                            "platform": "tvOS",
+                            "deploymentTarget": "1.1.0",
+                            "configFiles": [
+                                "debug": "Configs/$target_name/debug.xcconfig",
+                                "release": "Configs/${target_name}/release.xcconfig",
+                            ],
+                            "sources": ["${source}"],
+                        ],
+                    ],
+                    "schemeTemplates": [
+                        "base_scheme": [
+                            "build": [
+                                "parallelizeBuild": false,
+                                "buildImplicitDependencies": false,
+                                "targets": [
+                                    "Target1": "all",
+                                    "Target2": "testing",
+                                    "Target3": "none",
+                                    "Target4": ["testing": true],
+                                    "Target5": ["testing": false],
+                                    "Target6": ["test", "analyze"],
+                                ],
+                                "preActions": [
+                                    [
+                                        "script": "${pre-action-name}",
+                                        "name": "Before Build ${scheme_name}",
+                                        "settingsTarget": "Target1",
+                                    ],
+                                ],
+                            ],
+                            "test": [
+                                "config": "debug",
+                                "targets": [
+                                    "Target1",
+                                    [
+                                        "name": "Target2",
+                                        "parallelizable": true,
+                                        "randomExecutionOrder": true,
+                                        "skippedTests": ["Test/testExample()"],
+                                    ],
+                                ],
+                                "gatherCoverageData": true,
+                                "disableMainThreadChecker": true,
+                            ],
+                        ],
+                    ],
+                    "schemes": [
+                        "temp2": [
+                            "templates": ["base_scheme"],
+                            "templateAttributes": [
+                                "pre-action-name": "modified-name",
+                            ],
+                        ],
+                    ],
+                ])
+
+                let scheme = project.schemes.first!
+                let expectedTargets: [Scheme.BuildTarget] = [
+                    Scheme.BuildTarget(target: "Target1", buildTypes: BuildType.all),
+                    Scheme.BuildTarget(target: "Target2", buildTypes: [.testing, .analyzing]),
+                    Scheme.BuildTarget(target: "Target3", buildTypes: []),
+                    Scheme.BuildTarget(target: "Target4", buildTypes: [.testing]),
+                    Scheme.BuildTarget(target: "Target5", buildTypes: []),
+                    Scheme.BuildTarget(target: "Target6", buildTypes: [.testing, .analyzing]),
+                ]
+                try expect(scheme.name) == "temp2"
+                try expect(scheme.build.targets) == expectedTargets
+                try expect(scheme.build.preActions.first?.script) == "modified-name"
+                try expect(scheme.build.preActions.first?.name) == "Before Build temp2"
+                try expect(scheme.build.preActions.first?.settingsTarget) == "Target1"
+
+                try expect(scheme.build.parallelizeBuild) == false
+                try expect(scheme.build.buildImplicitDependencies) == false
+
+                let expectedTest = Scheme.Test(
+                    config: "debug",
+                    gatherCoverageData: true,
+                    disableMainThreadChecker: true,
+                    targets: [
+                        "Target1",
+                        Scheme.Test.TestTarget(
+                            name: "Target2",
+                            randomExecutionOrder: true,
+                            parallelizable: true,
+                            skippedTests: ["Test/testExample()"]
+                        ),
+                    ]
+                )
+                try expect(scheme.test) == expectedTest
+            }
+
             $0.it("parses settings") {
                 let project = try Project(path: fixturePath + "settings_test.yml")
                 let buildSettings: BuildSettings = ["SETTING": "value"]

From 682f1882889826fd29815efd541bd70f55bc9fd3 Mon Sep 17 00:00:00 2001
From: Brian Clymer <brian.clymer@hudl.com>
Date: Wed, 2 Oct 2019 09:06:15 -0500
Subject: [PATCH 2/6] Refactor to make scheme and target templates use the same
 code.

---
 Sources/ProjectSpec/Target.swift | 97 +++++++++++---------------------
 1 file changed, 33 insertions(+), 64 deletions(-)

diff --git a/Sources/ProjectSpec/Target.swift b/Sources/ProjectSpec/Target.swift
index bcab72ca..e31aee50 100644
--- a/Sources/ProjectSpec/Target.swift
+++ b/Sources/ProjectSpec/Target.swift
@@ -105,6 +105,12 @@ public struct Target: ProjectTarget {
     }
 }
 
+struct TemplateStructure {
+    let baseKey: String
+    let templatesKey: String
+    let nameToReplace: String
+}
+
 extension Target: CustomStringConvertible {
 
     public var description: String {
@@ -134,58 +140,6 @@ extension Target: PathContainer {
 
 extension Target {
 
-    static func resolveTargetTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
-        guard var targetsDictionary: [String: JSONDictionary] = jsonDictionary["targets"] as? [String: JSONDictionary] else {
-            return jsonDictionary
-        }
-
-        let targetTemplatesDictionary: [String: JSONDictionary] = jsonDictionary["targetTemplates"] as? [String: JSONDictionary] ?? [:]
-
-        // Recursively collects all nested template names of a given dictionary.
-        func collectTemplates(of jsonDictionary: JSONDictionary,
-                              into allTemplates: inout [String],
-                              insertAt insertionIndex: inout Int) {
-            guard let templates = jsonDictionary["templates"] as? [String] else {
-                return
-            }
-            for template in templates where !allTemplates.contains(template) {
-                guard let templateDictionary = targetTemplatesDictionary[template] else {
-                    continue
-                }
-                allTemplates.insert(template, at: insertionIndex)
-                collectTemplates(of: templateDictionary, into: &allTemplates, insertAt: &insertionIndex)
-                insertionIndex += 1
-            }
-        }
-
-        for (targetName, var target) in targetsDictionary {
-            var templates: [String] = []
-            var index: Int = 0
-            collectTemplates(of: target, into: &templates, insertAt: &index)
-            if !templates.isEmpty {
-                var mergedDictionary: JSONDictionary = [:]
-                for template in templates {
-                    if let templateDictionary = targetTemplatesDictionary[template] {
-                        mergedDictionary = templateDictionary.merged(onto: mergedDictionary)
-                    }
-                }
-                target = target.merged(onto: mergedDictionary)
-                target = target.replaceString("$target_name", with: targetName) // Will be removed in upcoming version
-                target = target.replaceString("${target_name}", with: targetName)
-                if let templateAttributes = target["templateAttributes"] as? [String: String] {
-                    for (templateAttribute, value) in templateAttributes {
-                        target = target.replaceString("${\(templateAttribute)}", with: value)
-                    }
-                }
-            }
-            targetsDictionary[targetName] = target
-        }
-
-        var jsonDictionary = jsonDictionary
-        jsonDictionary["targets"] = targetsDictionary
-        return jsonDictionary
-    }
-
     static func resolveMultiplatformTargets(jsonDictionary: JSONDictionary) -> JSONDictionary {
         guard let targetsDictionary: [String: JSONDictionary] = jsonDictionary["targets"] as? [String: JSONDictionary] else {
             return jsonDictionary
@@ -237,12 +191,26 @@ extension Target {
         return merged
     }
 
+    static func resolveTargetTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
+        return resolveTemplates(jsonDictionary: jsonDictionary,
+                                templateStructure: TemplateStructure(baseKey: "targets",
+                                                                     templatesKey: "targetTemplates",
+                                                                     nameToReplace: "target_name"))
+    }
+
     static func resolveSchemeTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
-        guard var schemesDictionary: [String: JSONDictionary] = jsonDictionary["schemes"] as? [String: JSONDictionary] else {
+        return resolveTemplates(jsonDictionary: jsonDictionary,
+                                templateStructure: TemplateStructure(baseKey: "schemes",
+                                                                     templatesKey: "schemeTemplates",
+                                                                     nameToReplace: "scheme_name"))
+    }
+
+    private static func resolveTemplates(jsonDictionary: JSONDictionary, templateStructure: TemplateStructure) -> JSONDictionary {
+        guard var baseDictionary: [String: JSONDictionary] = jsonDictionary[templateStructure.baseKey] as? [String: JSONDictionary] else {
             return jsonDictionary
         }
 
-        let schemeTemplatesDictionary: [String: JSONDictionary] = jsonDictionary["schemeTemplates"] as? [String: JSONDictionary] ?? [:]
+        let templatesDictionary: [String: JSONDictionary] = jsonDictionary[templateStructure.templatesKey] as? [String: JSONDictionary] ?? [:]
 
         // Recursively collects all nested template names of a given dictionary.
         func collectTemplates(of jsonDictionary: JSONDictionary,
@@ -252,7 +220,7 @@ extension Target {
                 return
             }
             for template in templates where !allTemplates.contains(template) {
-                guard let templateDictionary = schemeTemplatesDictionary[template] else {
+                guard let templateDictionary = templatesDictionary[template] else {
                     continue
                 }
                 allTemplates.insert(template, at: insertionIndex)
@@ -261,30 +229,31 @@ extension Target {
             }
         }
 
-        for (schemeName, var scheme) in schemesDictionary {
+        for (referenceName, var reference) in baseDictionary {
             var templates: [String] = []
             var index: Int = 0
-            collectTemplates(of: scheme, into: &templates, insertAt: &index)
+            collectTemplates(of: reference, into: &templates, insertAt: &index)
             if !templates.isEmpty {
                 var mergedDictionary: JSONDictionary = [:]
                 for template in templates {
-                    if let templateDictionary = schemeTemplatesDictionary[template] {
+                    if let templateDictionary = templatesDictionary[template] {
                         mergedDictionary = templateDictionary.merged(onto: mergedDictionary)
                     }
                 }
-                scheme = scheme.merged(onto: mergedDictionary)
-                scheme = scheme.replaceString("${scheme_name}", with: schemeName)
-                if let templateAttributes = scheme["templateAttributes"] as? [String: String] {
+                reference = reference.merged(onto: mergedDictionary)
+                reference = reference.replaceString("$\(templateStructure.nameToReplace)", with: referenceName) // Will be removed in upcoming version
+                reference = reference.replaceString("${\(templateStructure.nameToReplace)}", with: referenceName)
+                if let templateAttributes = reference["templateAttributes"] as? [String: String] {
                     for (templateAttribute, value) in templateAttributes {
-                        scheme = scheme.replaceString("${\(templateAttribute)}", with: value)
+                        reference = reference.replaceString("${\(templateAttribute)}", with: value)
                     }
                 }
             }
-            schemesDictionary[schemeName] = scheme
+            baseDictionary[referenceName] = reference
         }
 
         var jsonDictionary = jsonDictionary
-        jsonDictionary["schemes"] = schemesDictionary
+        jsonDictionary[templateStructure.baseKey] = baseDictionary
         return jsonDictionary
     }
 }

From 6e5766a2bcfad70f42ae2648ed3f2e018d85df38 Mon Sep 17 00:00:00 2001
From: Brian Clymer <crdnilfan@gmail.com>
Date: Wed, 2 Oct 2019 10:40:15 -0500
Subject: [PATCH 3/6] Ensure that target names can be changed by template
 attributes.

---
 Sources/ProjectSpec/Scheme.swift              |  2 +-
 Sources/ProjectSpec/SpecFile.swift            |  4 +++-
 Tests/XcodeGenKitTests/SpecLoadingTests.swift | 20 ++++++++++---------
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/Sources/ProjectSpec/Scheme.swift b/Sources/ProjectSpec/Scheme.swift
index cc53b13a..f7ea7627 100644
--- a/Sources/ProjectSpec/Scheme.swift
+++ b/Sources/ProjectSpec/Scheme.swift
@@ -238,7 +238,7 @@ public struct Scheme: Equatable {
         }
     }
 
-    public struct BuildTarget: Equatable {
+    public struct BuildTarget: Equatable, Hashable {
         public var target: String
         public var buildTypes: [BuildType]
 
diff --git a/Sources/ProjectSpec/SpecFile.swift b/Sources/ProjectSpec/SpecFile.swift
index 6983f0ab..59947313 100644
--- a/Sources/ProjectSpec/SpecFile.swift
+++ b/Sources/ProjectSpec/SpecFile.swift
@@ -158,7 +158,9 @@ extension Dictionary where Key == String, Value: Any {
     func replaceString(_ template: String, with replacement: String) -> JSONDictionary {
         var replaced: JSONDictionary = self
         for (key, value) in self {
-            replaced[key] = replace(value: value, template, with: replacement)
+            let newKey = key.replacingOccurrences(of: template, with: replacement)
+            replaced.removeValue(forKey: key)
+            replaced[newKey] = replace(value: value, template, with: replacement)
         }
         return replaced
     }
diff --git a/Tests/XcodeGenKitTests/SpecLoadingTests.swift b/Tests/XcodeGenKitTests/SpecLoadingTests.swift
index 94a461e4..a01a4bf9 100644
--- a/Tests/XcodeGenKitTests/SpecLoadingTests.swift
+++ b/Tests/XcodeGenKitTests/SpecLoadingTests.swift
@@ -890,9 +890,9 @@ class SpecLoadingTests: XCTestCase {
                                 "parallelizeBuild": false,
                                 "buildImplicitDependencies": false,
                                 "targets": [
-                                    "Target1": "all",
+                                    "Target${name_1}": "all",
                                     "Target2": "testing",
-                                    "Target3": "none",
+                                    "Target${name_3}": "none",
                                     "Target4": ["testing": true],
                                     "Target5": ["testing": false],
                                     "Target6": ["test", "analyze"],
@@ -901,14 +901,14 @@ class SpecLoadingTests: XCTestCase {
                                     [
                                         "script": "${pre-action-name}",
                                         "name": "Before Build ${scheme_name}",
-                                        "settingsTarget": "Target1",
+                                        "settingsTarget": "Target${name_1}",
                                     ],
                                 ],
                             ],
                             "test": [
                                 "config": "debug",
                                 "targets": [
-                                    "Target1",
+                                    "Target${name_1}",
                                     [
                                         "name": "Target2",
                                         "parallelizable": true,
@@ -926,6 +926,8 @@ class SpecLoadingTests: XCTestCase {
                             "templates": ["base_scheme"],
                             "templateAttributes": [
                                 "pre-action-name": "modified-name",
+                                "name_1": "FirstTarget",
+                                "name_3": "ThirdTarget",
                             ],
                         ],
                     ],
@@ -933,18 +935,18 @@ class SpecLoadingTests: XCTestCase {
 
                 let scheme = project.schemes.first!
                 let expectedTargets: [Scheme.BuildTarget] = [
-                    Scheme.BuildTarget(target: "Target1", buildTypes: BuildType.all),
+                    Scheme.BuildTarget(target: "TargetFirstTarget", buildTypes: BuildType.all),
                     Scheme.BuildTarget(target: "Target2", buildTypes: [.testing, .analyzing]),
-                    Scheme.BuildTarget(target: "Target3", buildTypes: []),
+                    Scheme.BuildTarget(target: "TargetThirdTarget", buildTypes: []),
                     Scheme.BuildTarget(target: "Target4", buildTypes: [.testing]),
                     Scheme.BuildTarget(target: "Target5", buildTypes: []),
                     Scheme.BuildTarget(target: "Target6", buildTypes: [.testing, .analyzing]),
                 ]
                 try expect(scheme.name) == "temp2"
-                try expect(scheme.build.targets) == expectedTargets
+                try expect(Set(scheme.build.targets)) == Set(expectedTargets)
                 try expect(scheme.build.preActions.first?.script) == "modified-name"
                 try expect(scheme.build.preActions.first?.name) == "Before Build temp2"
-                try expect(scheme.build.preActions.first?.settingsTarget) == "Target1"
+                try expect(scheme.build.preActions.first?.settingsTarget) == "TargetFirstTarget"
 
                 try expect(scheme.build.parallelizeBuild) == false
                 try expect(scheme.build.buildImplicitDependencies) == false
@@ -954,7 +956,7 @@ class SpecLoadingTests: XCTestCase {
                     gatherCoverageData: true,
                     disableMainThreadChecker: true,
                     targets: [
-                        "Target1",
+                        "TargetFirstTarget",
                         Scheme.Test.TestTarget(
                             name: "Target2",
                             randomExecutionOrder: true,

From 7152d6aa9fbe45e210dc4d7adcb55f5cb62a72c8 Mon Sep 17 00:00:00 2001
From: Brian Clymer <brian.clymer@hudl.com>
Date: Sun, 6 Oct 2019 15:33:27 -0500
Subject: [PATCH 4/6] Address CR.

---
 Sources/ProjectSpec/Project.swift  |  2 +-
 Sources/ProjectSpec/SpecFile.swift |  4 +-
 Sources/ProjectSpec/Target.swift   | 72 ---------------------------
 Sources/ProjectSpec/Template.swift | 78 ++++++++++++++++++++++++++++++
 4 files changed, 82 insertions(+), 74 deletions(-)
 create mode 100644 Sources/ProjectSpec/Template.swift

diff --git a/Sources/ProjectSpec/Project.swift b/Sources/ProjectSpec/Project.swift
index 05905ccb..da092574 100644
--- a/Sources/ProjectSpec/Project.swift
+++ b/Sources/ProjectSpec/Project.swift
@@ -191,7 +191,7 @@ extension Project {
         // as well as platform specific templates in multi-platform targets
         jsonDictionary = Target.resolveMultiplatformTargets(jsonDictionary: jsonDictionary)
         jsonDictionary = Target.resolveTargetTemplates(jsonDictionary: jsonDictionary)
-        jsonDictionary = Target.resolveSchemeTemplates(jsonDictionary: jsonDictionary)
+        jsonDictionary = Scheme.resolveSchemeTemplates(jsonDictionary: jsonDictionary)
         jsonDictionary = Target.resolveMultiplatformTargets(jsonDictionary: jsonDictionary)
 
         return jsonDictionary
diff --git a/Sources/ProjectSpec/SpecFile.swift b/Sources/ProjectSpec/SpecFile.swift
index 59947313..ef2ba36d 100644
--- a/Sources/ProjectSpec/SpecFile.swift
+++ b/Sources/ProjectSpec/SpecFile.swift
@@ -159,7 +159,9 @@ extension Dictionary where Key == String, Value: Any {
         var replaced: JSONDictionary = self
         for (key, value) in self {
             let newKey = key.replacingOccurrences(of: template, with: replacement)
-            replaced.removeValue(forKey: key)
+            if newKey != key {
+                replaced.removeValue(forKey: key)
+            }
             replaced[newKey] = replace(value: value, template, with: replacement)
         }
         return replaced
diff --git a/Sources/ProjectSpec/Target.swift b/Sources/ProjectSpec/Target.swift
index e31aee50..8fa85a66 100644
--- a/Sources/ProjectSpec/Target.swift
+++ b/Sources/ProjectSpec/Target.swift
@@ -105,12 +105,6 @@ public struct Target: ProjectTarget {
     }
 }
 
-struct TemplateStructure {
-    let baseKey: String
-    let templatesKey: String
-    let nameToReplace: String
-}
-
 extension Target: CustomStringConvertible {
 
     public var description: String {
@@ -190,72 +184,6 @@ extension Target {
         merged["targets"] = crossPlatformTargets
         return merged
     }
-
-    static func resolveTargetTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
-        return resolveTemplates(jsonDictionary: jsonDictionary,
-                                templateStructure: TemplateStructure(baseKey: "targets",
-                                                                     templatesKey: "targetTemplates",
-                                                                     nameToReplace: "target_name"))
-    }
-
-    static func resolveSchemeTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
-        return resolveTemplates(jsonDictionary: jsonDictionary,
-                                templateStructure: TemplateStructure(baseKey: "schemes",
-                                                                     templatesKey: "schemeTemplates",
-                                                                     nameToReplace: "scheme_name"))
-    }
-
-    private static func resolveTemplates(jsonDictionary: JSONDictionary, templateStructure: TemplateStructure) -> JSONDictionary {
-        guard var baseDictionary: [String: JSONDictionary] = jsonDictionary[templateStructure.baseKey] as? [String: JSONDictionary] else {
-            return jsonDictionary
-        }
-
-        let templatesDictionary: [String: JSONDictionary] = jsonDictionary[templateStructure.templatesKey] as? [String: JSONDictionary] ?? [:]
-
-        // Recursively collects all nested template names of a given dictionary.
-        func collectTemplates(of jsonDictionary: JSONDictionary,
-                              into allTemplates: inout [String],
-                              insertAt insertionIndex: inout Int) {
-            guard let templates = jsonDictionary["templates"] as? [String] else {
-                return
-            }
-            for template in templates where !allTemplates.contains(template) {
-                guard let templateDictionary = templatesDictionary[template] else {
-                    continue
-                }
-                allTemplates.insert(template, at: insertionIndex)
-                collectTemplates(of: templateDictionary, into: &allTemplates, insertAt: &insertionIndex)
-                insertionIndex += 1
-            }
-        }
-
-        for (referenceName, var reference) in baseDictionary {
-            var templates: [String] = []
-            var index: Int = 0
-            collectTemplates(of: reference, into: &templates, insertAt: &index)
-            if !templates.isEmpty {
-                var mergedDictionary: JSONDictionary = [:]
-                for template in templates {
-                    if let templateDictionary = templatesDictionary[template] {
-                        mergedDictionary = templateDictionary.merged(onto: mergedDictionary)
-                    }
-                }
-                reference = reference.merged(onto: mergedDictionary)
-                reference = reference.replaceString("$\(templateStructure.nameToReplace)", with: referenceName) // Will be removed in upcoming version
-                reference = reference.replaceString("${\(templateStructure.nameToReplace)}", with: referenceName)
-                if let templateAttributes = reference["templateAttributes"] as? [String: String] {
-                    for (templateAttribute, value) in templateAttributes {
-                        reference = reference.replaceString("${\(templateAttribute)}", with: value)
-                    }
-                }
-            }
-            baseDictionary[referenceName] = reference
-        }
-
-        var jsonDictionary = jsonDictionary
-        jsonDictionary[templateStructure.baseKey] = baseDictionary
-        return jsonDictionary
-    }
 }
 
 extension Target: Equatable {
diff --git a/Sources/ProjectSpec/Template.swift b/Sources/ProjectSpec/Template.swift
new file mode 100644
index 00000000..974fe3d4
--- /dev/null
+++ b/Sources/ProjectSpec/Template.swift
@@ -0,0 +1,78 @@
+import Foundation
+import JSONUtilities
+
+struct TemplateStructure {
+    let baseKey: String
+    let templatesKey: String
+    let nameToReplace: String
+}
+
+extension Target {
+    static func resolveTargetTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
+        return resolveTemplates(jsonDictionary: jsonDictionary,
+                                templateStructure: TemplateStructure(baseKey: "targets",
+                                                                     templatesKey: "targetTemplates",
+                                                                     nameToReplace: "target_name"))
+    }
+}
+
+extension Scheme {
+    static func resolveSchemeTemplates(jsonDictionary: JSONDictionary) -> JSONDictionary {
+        return resolveTemplates(jsonDictionary: jsonDictionary,
+                                templateStructure: TemplateStructure(baseKey: "schemes",
+                                                                     templatesKey: "schemeTemplates",
+                                                                     nameToReplace: "scheme_name"))
+    }
+}
+
+private func resolveTemplates(jsonDictionary: JSONDictionary, templateStructure: TemplateStructure) -> JSONDictionary {
+    guard var baseDictionary: [String: JSONDictionary] = jsonDictionary[templateStructure.baseKey] as? [String: JSONDictionary] else {
+        return jsonDictionary
+    }
+
+    let templatesDictionary: [String: JSONDictionary] = jsonDictionary[templateStructure.templatesKey] as? [String: JSONDictionary] ?? [:]
+
+    // Recursively collects all nested template names of a given dictionary.
+    func collectTemplates(of jsonDictionary: JSONDictionary,
+                          into allTemplates: inout [String],
+                          insertAt insertionIndex: inout Int) {
+        guard let templates = jsonDictionary["templates"] as? [String] else {
+            return
+        }
+        for template in templates where !allTemplates.contains(template) {
+            guard let templateDictionary = templatesDictionary[template] else {
+                continue
+            }
+            allTemplates.insert(template, at: insertionIndex)
+            collectTemplates(of: templateDictionary, into: &allTemplates, insertAt: &insertionIndex)
+            insertionIndex += 1
+        }
+    }
+
+    for (referenceName, var reference) in baseDictionary {
+        var templates: [String] = []
+        var index: Int = 0
+        collectTemplates(of: reference, into: &templates, insertAt: &index)
+        if !templates.isEmpty {
+            var mergedDictionary: JSONDictionary = [:]
+            for template in templates {
+                if let templateDictionary = templatesDictionary[template] {
+                    mergedDictionary = templateDictionary.merged(onto: mergedDictionary)
+                }
+            }
+            reference = reference.merged(onto: mergedDictionary)
+            reference = reference.replaceString("$\(templateStructure.nameToReplace)", with: referenceName) // Will be removed in upcoming version
+            reference = reference.replaceString("${\(templateStructure.nameToReplace)}", with: referenceName)
+            if let templateAttributes = reference["templateAttributes"] as? [String: String] {
+                for (templateAttribute, value) in templateAttributes {
+                    reference = reference.replaceString("${\(templateAttribute)}", with: value)
+                }
+            }
+        }
+        baseDictionary[referenceName] = reference
+    }
+
+    var jsonDictionary = jsonDictionary
+    jsonDictionary[templateStructure.baseKey] = baseDictionary
+    return jsonDictionary
+}

From ba34891aae8e16c64abad1fdb24d025e35c4ae5c Mon Sep 17 00:00:00 2001
From: Brian Clymer <brian.clymer@hudl.com>
Date: Sun, 6 Oct 2019 15:48:10 -0500
Subject: [PATCH 5/6] Add changelog and docs.

---
 CHANGELOG.md        |  4 ++++
 Docs/ProjectSpec.md | 36 +++++++++++++++++++++++++++++++++++-
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ba662adf..152f4341 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Next Version
 
+#### Added
+
+- Scheme Templates [#672](https://github.com/yonaskolb/XcodeGen/pull/672) @bclymer
+
 #### Fixed
 - Fixed macOS unit test setting preset [#665](https://github.com/yonaskolb/XcodeGen/pull/665) @yonaskolb
 - Add `rcproject` files to sources build phase instead of resources [#669](https://github.com/yonaskolb/XcodeGen/pull/669) @Qusic
diff --git a/Docs/ProjectSpec.md b/Docs/ProjectSpec.md
index 0321f222..61aa3bfa 100644
--- a/Docs/ProjectSpec.md
+++ b/Docs/ProjectSpec.md
@@ -23,6 +23,7 @@
 - [Aggregate Target](#aggregate-target)
 - [Target Template](#target-template)
 - [Scheme](#scheme)
+  - [Scheme Template](#scheme-template)
 - [Swift Package](#swift-package)
 
 ## General
@@ -781,6 +782,39 @@ schemes:
       revealArchiveInOrganizer: false
 ```
 
+### Scheme Template
+
+This is a template that can be referenced from a normal scheme using the `templates` property. The properties of this template are the same as a [Scheme](#scheme). This functions identically in practice to [Target Template](#target-template).
+Any instances of `${scheme_name}` within each template will be replaced by the final scheme name which references the template.
+Any attributes defined within a targets `templateAttributes` will be used to replace any attribute references in the template using the syntax `${attribute_name}`.
+
+```yaml
+schemes:
+  MyModule:
+    templates:
+      - FeatureModuleScheme
+    templateAttributes:
+      testTargetName: MyModuleTests
+
+schemeTemplates:
+  FeatureModuleScheme:
+    templates:
+      - TestScheme
+    build:
+      targets:
+       ${scheme_name}: build
+
+  TestScheme:
+    test:
+      gatherCoverageData: true
+      targets:
+        - name: ${testTargetName}
+          parallelizable: true
+          randomExecutionOrder: true
+```
+
+The result will be a scheme that builds `MyModule` when you request a build, and will test against `MyModuleTests` when you request to run tests. This is particularly useful when you work in a very modular application and each module has a similar structure.
+
 ## Swift Package
 Swift packages are defined at a project level, and then linked to individual targets via a [Dependency](#dependency).
 
@@ -804,4 +838,4 @@ targets:
   App:
     dependencies:
       - package: Yams
-```
\ No newline at end of file
+```

From 5348e4080b0dea842ae3ce2a1103c297ef935c44 Mon Sep 17 00:00:00 2001
From: Brian Clymer <brian.clymer@hudl.com>
Date: Mon, 7 Oct 2019 19:39:29 -0500
Subject: [PATCH 6/6] Missed a target reference.

---
 Docs/ProjectSpec.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Docs/ProjectSpec.md b/Docs/ProjectSpec.md
index 61aa3bfa..204cd230 100644
--- a/Docs/ProjectSpec.md
+++ b/Docs/ProjectSpec.md
@@ -786,7 +786,7 @@ schemes:
 
 This is a template that can be referenced from a normal scheme using the `templates` property. The properties of this template are the same as a [Scheme](#scheme). This functions identically in practice to [Target Template](#target-template).
 Any instances of `${scheme_name}` within each template will be replaced by the final scheme name which references the template.
-Any attributes defined within a targets `templateAttributes` will be used to replace any attribute references in the template using the syntax `${attribute_name}`.
+Any attributes defined within a scheme's `templateAttributes` will be used to replace any attribute references in the template using the syntax `${attribute_name}`.
 
 ```yaml
 schemes: