action_TestSummaries.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>FormatVersion</key>
	<string>1.2</string>
	<key>RunDestination</key>
	<dict>
		<key>Name</key>
		<string>iPhone Retina (4-inch)</string>
		<key>TargetArchitecture</key>
		<string>i386</string>
		<key>TargetDevice</key>
		<dict>
			<key>IsConcreteDevice</key>
			<true/>
			<key>ModelCode</key>
			<string>iPhone5,1</string>
			<key>ModelName</key>
			<string>iPhone Retina (4-inch)</string>
			<key>ModelUTI</key>
			<string>com.apple.iphone-5-a1428-black</string>
			<key>Name</key>
			<string>iPhone Retina (4-inch)</string>
			<key>NativeArchitecture</key>
			<string>i386</string>
			<key>OperatingSystemVersion</key>
			<string>7.0</string>
			<key>OperatingSystemVersionWithBuildNumber</key>
			<string>7.0</string>
			<key>Platform</key>
			<dict>
				<key>Identifier</key>
				<string>com.apple.platform.iphonesimulator</string>
				<key>Name</key>
				<string>iOS Simulator</string>
			</dict>
		</dict>
		<key>TargetSDK</key>
		<dict>
			<key>Identifier</key>
			<string>iphonesimulator7.0</string>
			<key>Name</key>
			<string>Simulator - iOS 7.0</string>
			<key>OperatingSystemVersion</key>
			<string>7.0</string>
		</dict>
	</dict>
	<key>TestableSummaries</key>
	<array>
		<dict>
			<key>ProjectPath</key>
			<string>HelloCI.xcodeproj</string>
			<key>TargetName</key>
			<string>HelloCITests</string>
			<key>TestName</key>
			<string>HelloCITests</string>
			<key>TestObjectClass</key>
			<string>IDESchemeActionTestableSummary</string>
			<key>Tests</key>
			<array>
				<dict>
					<key>Subtests</key>
					<array>
						<dict>
							<key>Subtests</key>
							<array>
								<dict>
									<key>Subtests</key>
									<array>
										<dict>
											<key>TestIdentifier</key>
											<string>HelloCITests/test_Should_be_a_monkey</string>
											<key>TestName</key>
											<string>test_Should_be_a_monkey</string>
											<key>TestObjectClass</key>
											<string>IDESchemeActionTestSummary</string>
											<key>TestStatus</key>
											<string>Success</string>
											<key>TestSummaryGUID</key>
											<string>E83EB1D0-25B8-474C-9BC3-D7E519D0242E</string>
										</dict>
										<dict>
											<key>TestIdentifier</key>
											<string>HelloCITests/testAnotherThing</string>
											<key>TestName</key>
											<string>testAnotherThing</string>
											<key>TestObjectClass</key>
											<string>IDESchemeActionTestSummary</string>
											<key>TestStatus</key>
											<string>Success</string>
											<key>TestSummaryGUID</key>
											<string>59804847-83F2-4B51-BA9F-083343AC9D3F</string>
										</dict>
									</array>
									<key>TestIdentifier</key>
									<string>HelloCITests</string>
									<key>TestName</key>
									<string>HelloCITests</string>
									<key>TestObjectClass</key>
									<string>IDESchemeActionTestSummaryGroup</string>
								</dict>
							</array>
							<key>TestIdentifier</key>
							<string>HelloCITests.xctest</string>
							<key>TestName</key>
							<string>HelloCITests.xctest</string>
							<key>TestObjectClass</key>
							<string>IDESchemeActionTestSummaryGroup</string>
						</dict>
					</array>
					<key>TestIdentifier</key>
					<string>All tests</string>
					<key>TestName</key>
					<string>All tests</string>
					<key>TestObjectClass</key>
					<string>IDESchemeActionTestSummaryGroup</string>
				</dict>
			</array>
		</dict>
	</array>
</dict>
</plist>

Output buy default in /Library/Developer/Xcode/DerivedData/[YOUR PROJECT NAME POSSIBLY WITH UUIDness]/TestResults/2014-02-10 19.02.36 +0000.xctestresults/

You can override this by setting -resultBundlePath [WHERE YOU WANT THIS FILE] as an xcodebuild option.