Add support for one zero and yes no boolean strings in environement variables provider

Sources/Configuration/Providers/EnvironmentVariables/EnvironmentVariablesProvider.swift

@@ -142,6 +142,16 @@ public struct EnvironmentVariablesProvider: Sendable {
 
         /// A decoder of arrays from a string.
         var arrayDecoder: EnvironmentValueArrayDecoder
+
+        /// A decoder of bool values from a string.
+        static func decodeBool(from string: String) -> Bool? {
+            let stringLowercased = string.lowercased()
+            return switch stringLowercased {
+            case "yes", "1": true
+            case "no", "0": false
+            default: Bool(stringLowercased)
+            }
+        }
     }
 
     /// The underlying snapshot of the provider.
@@ -393,7 +403,7 @@ extension EnvironmentVariablesProvider.Snapshot {
             }
             content = .double(doubleValue)
         case .bool:
-            guard let boolValue = Bool(stringValue) else {
+            guard let boolValue = Self.decodeBool(from: stringValue) else {
                 try throwMismatch()
             }
             content = .bool(boolValue)
@@ -426,7 +436,7 @@ extension EnvironmentVariablesProvider.Snapshot {
         case .boolArray:
             let arrayValue = arrayDecoder.decode(stringValue)
             let boolArray = try arrayValue.map { stringValue in
-                guard let boolValue = Bool(stringValue) else {
+                guard let boolValue = Self.decodeBool(from: stringValue) else {
                     try throwMismatch()
                 }
                 return boolValue

Tests/ConfigurationTests/EnvironmentVariablesProviderTests.swift

@@ -68,6 +68,64 @@ struct EnvironmentVariablesProviderTests {
         #expect(provider.debugDescription == expectedDebugDescription)
     }
 
+    @available(Configuration 1.0, *)
+    @Test func decodeBoolFromString() throws {
+        let sut = EnvironmentVariablesProvider.Snapshot.decodeBool
+        let cases: [(expected: Bool?, input: [String])] = [
+            (true, ["1"]),
+            (false, ["0"]),
+            (true, ["Yes", "yes", "YES", "yES"]),
+            (false, ["No", "no", "NO", "nO"]),
+            (true, ["true", "TRUE", "trUe"]),
+            (false, ["false", "FALSE", "faLse"]),
+            (nil, ["", " ", "_true_", "_false_", "_yes_", "_no_", "_1_", "_0_", "11", "00"]),
+        ]
+        for (expected, inputs) in cases {
+            for input in inputs {
+                #expect(sut(input) == expected, "input: \(input)")
+            }
+        }
+    }
+
+    @available(Configuration 1.0, *)
+    @Test func valueForKeyOfBoolAndBoolArrayTypes() throws {
+        let sut = EnvironmentVariablesProvider(
+            environmentVariables: [
+                "BOOL_TRUE": "true",
+                "BOOL_FALSE": "false",
+                "BOOL_1": "1",
+                "BOOL_0": "0",
+                "BOOL_YES": "YES",
+                "BOOL_NO": "NO",
+                "BOOL_THROWS_ERROR_EMPTY": "",
+                "BOOL_THROWS_ERROR_NOT_BOOL_STRING": "2",
+                "BOOLY_ARRAY_TRUE": "true,1,,YES",
+                "BOOLY_ARRAY_FALSE": "false,0,NO",
+                "BOOLY_ARRAY_THROWS_1": "true,1,YESS",
+                "BOOLY_ARRAY_THROWS_2": "false,00,no",
+                "BOOLY_ARRAY_THROWS_3": "false, ,no",
+            ])
+        #expect(try sut.value(forKey: "BOOL_TRUE", type: .bool).value == true)
+        #expect(try sut.value(forKey: "BOOL_FALSE", type: .bool).value == false)
+        #expect(try sut.value(forKey: "BOOL_1", type: .bool).value == true)
+        #expect(try sut.value(forKey: "BOOL_0", type: .bool).value == false)
+        #expect(try sut.value(forKey: "BOOL_YES", type: .bool).value == true)
+        #expect(try sut.value(forKey: "BOOL_NO", type: .bool).value == false)
+        #expect(throws: ConfigError.self) { try sut.value(forKey: "BOOL_THROWS_ERROR_EMPTY", type: .bool) }
+        #expect(throws: ConfigError.self) { try sut.value(forKey: "BOOL_THROWS_ERROR_NOT_BOOL_STRING", type: .bool) }
+        #expect(
+            try sut.value(forKey: "BOOLY_ARRAY_TRUE", type: .boolArray).value
+                == .init([true, true, true], isSecret: false)
+        )
+        #expect(
+            try sut.value(forKey: "BOOLY_ARRAY_FALSE", type: .boolArray).value
+                == .init([false, false, false], isSecret: false)
+        )
+        #expect(throws: ConfigError.self) { try sut.value(forKey: "BOOLY_ARRAY_THROWS_1", type: .boolArray) }
+        #expect(throws: ConfigError.self) { try sut.value(forKey: "BOOLY_ARRAY_THROWS_2", type: .boolArray) }
+        #expect(throws: ConfigError.self) { try sut.value(forKey: "BOOLY_ARRAY_THROWS_3", type: .boolArray) }
+    }
+
     @available(Configuration 1.0, *)
     @Test func compat() async throws {
         try await ProviderCompatTest(provider: provider).runTest()