feat: kustomize fieldpath matcher flag

cmd/command.go

@@ -103,6 +103,18 @@ func Command() *cobra.Command { //nolint:funlen
 		"",
 		"exclude resources by executing a script")
 
+	// Define --fieldpath flag.
+	mf.StringSliceErrorMatcher(matcher.NewFieldPathMatcher,
+		"fieldpath",
+		nil,
+		"include resources by kustomize fieldpath")
+
+	// Define --not-fieldpath flag.
+	mf.StringSliceErrorMatcher(matcher.NewFieldPathMatcher,
+		"not-fieldpath",
+		nil,
+		"exclude resources by kustomize fieldpath")
+
 	// Define --jsonpath flag.
 	mf.StringSliceErrorMatcher(matcher.NewJsonpathMatcher,
 		"jsonpath",

go.mod

@@ -13,30 +13,40 @@ require (
 	golang.org/x/term v0.35.0
 	k8s.io/apimachinery v0.34.1
 	k8s.io/client-go v0.34.1
+	sigs.k8s.io/kustomize/kyaml v0.21.0
 	sigs.k8s.io/yaml v1.6.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/fxamacker/cbor/v2 v2.9.0 // indirect
+	github.com/go-errors/errors v1.4.2 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-openapi/jsonpointer v0.21.0 // indirect
+	github.com/go-openapi/jsonreference v0.20.2 // indirect
+	github.com/go-openapi/swag v0.23.0 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/google/gnostic-models v0.7.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
-	github.com/kr/pretty v0.3.1 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/stretchr/testify v1.11.1 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
+	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/net v0.44.0 // indirect
 	golang.org/x/sys v0.36.0 // indirect
 	golang.org/x/text v0.29.0 // indirect
-	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
+	google.golang.org/protobuf v1.36.5 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/klog/v2 v2.130.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20250710124328-f3f2b991d03b // indirect
 	k8s.io/utils v0.0.0-20250820121507-0af2bda4dd1d // indirect
 	sigs.k8s.io/json v0.0.0-20250730193827-2d320260d730 // indirect
 	sigs.k8s.io/randfill v1.0.0 // indirect

go.sum

@@ -8,18 +8,32 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fxamacker/cbor/v2 v2.9.0 h1:NpKPmjDBgUfBms6tr6JZkTHtfFGcMKsw3eGcmD/sapM=
 github.com/fxamacker/cbor/v2 v2.9.0/go.mod h1:vM4b+DJCtHn+zz7h3FFp/hDAI9WNWCsZj23V5ytsSxQ=
+github.com/go-errors/errors v1.4.2 h1:J6MZopCL4uSllY1OfXM374weqZFFItUbrImctkmUxIA=
+github.com/go-errors/errors v1.4.2/go.mod h1:sIVyrIiJhuEF+Pj9Ebtd6P/rEYROXFi3BopGUQ5a5Og=
 github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
 github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-openapi/jsonpointer v0.19.6/go.mod h1:osyAmYz/mB/C3I+WsTTSgw1ONzaLJoLCyoi6/zppojs=
+github.com/go-openapi/jsonpointer v0.21.0 h1:YgdVicSA9vH5RiHs9TZW5oyafXZFc6+2Vc1rr/O9oNQ=
+github.com/go-openapi/jsonpointer v0.21.0/go.mod h1:IUyH9l/+uyhIYQ/PXVA41Rexl+kOkAPDdXEYns6fzUY=
+github.com/go-openapi/jsonreference v0.20.2 h1:3sVjiK66+uXK/6oQ8xgcRKcFgQ5KXa2KvnJRumpMGbE=
+github.com/go-openapi/jsonreference v0.20.2/go.mod h1:Bl1zwGIM8/wsvqjsOQLJ/SH+En5Ap4rVB5KVcIDZG2k=
+github.com/go-openapi/swag v0.22.3/go.mod h1:UzaqsxGiab7freDnrUUra0MwWfN/q7tE4j+VcZ0yl14=
+github.com/go-openapi/swag v0.23.0 h1:vsEVJDUo2hPJ2tu0/Xc+4noaxyEffXNIs3cOULZ+GrE=
+github.com/go-openapi/swag v0.23.0/go.mod h1:esZ8ITTYEsH1V2trKHjAN8Ai7xHb8RV+YSZ577vPjgQ=
 github.com/gobwas/glob v0.2.3 h1:A4xDbljILXROh+kObIiy5kIaPYD8e96x1tgBhUI5J+Y=
 github.com/gobwas/glob v0.2.3/go.mod h1:d3Ez4x06l9bZtSvzIay5+Yzi0fmZzPgnTbPcKjJAkT8=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
+github.com/google/gnostic-models v0.7.0 h1:qwTtogB15McXDaNqTZdzPJRHvaVJlAl+HVQnLmJEJxo=
+github.com/google/gnostic-models v0.7.0/go.mod h1:whL5G0m6dmc5cPxKc5bdKdEN3UjI7OUGxBlw57miDrQ=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
+github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/joshdk/buildversion v0.1.0 h1:AeCFYqV2zZI6Q5pUDNi9YzX15Kmm7UnHKsC8yN2YIsk=
 github.com/joshdk/buildversion v0.1.0/go.mod h1:M/dUoVcv7TeUJ72r8NdyccLHO/7aaKUT8CdKOSb6FfU=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
@@ -33,6 +47,8 @@ github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
+github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6TULQc=
 github.com/mattn/go-runewidth v0.0.16/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
@@ -41,7 +57,6 @@ github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJ
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee h1:W5t00kpgFdJifH4BDsTlE89Zl93FEloxaWZfGcifgq8=
 github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
-github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
@@ -50,9 +65,8 @@ github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
 github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
 github.com/rodaine/table v1.3.0 h1:4/3S3SVkHnVZX91EHFvAMV7K42AnJ0XuymRR2C5HlGE=
 github.com/rodaine/table v1.3.0/go.mod h1:47zRsHar4zw0jgxGxL9YtFfs7EGN6B/TaS+/Dmk4WxU=
-github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
-github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
-github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
+github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
+github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/spf13/cobra v1.10.1 h1:lJeBwCfmrnXthfAupyUTzJ/J4Nc1RsHC/mSRU2dll/s=
 github.com/spf13/cobra v1.10.1/go.mod h1:7SmJGaTHFVBY0jW4NXGluQoLvhqFQM+6XSKD+P4XaB0=
@@ -66,6 +80,7 @@ github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
@@ -111,6 +126,8 @@ golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/protobuf v1.36.5 h1:tPhr+woSbjfYvY6/GPufUoYizxw1cF/yFoxJ2fmpwlM=
+google.golang.org/protobuf v1.36.5/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
@@ -125,10 +142,14 @@ k8s.io/client-go v0.34.1 h1:ZUPJKgXsnKwVwmKKdPfw4tB58+7/Ik3CrjOEhsiZ7mY=
 k8s.io/client-go v0.34.1/go.mod h1:kA8v0FP+tk6sZA0yKLRG67LWjqufAoSHA2xVGKw9Of8=
 k8s.io/klog/v2 v2.130.1 h1:n9Xl7H1Xvksem4KFG4PYbdQCQxqc/tTUyrgXaOhHSzk=
 k8s.io/klog/v2 v2.130.1/go.mod h1:3Jpz1GvMt720eyJH1ckRHK1EDfpxISzJ7I9OYgaDtPE=
+k8s.io/kube-openapi v0.0.0-20250710124328-f3f2b991d03b h1:MloQ9/bdJyIu9lb1PzujOPolHyvO06MXG5TUIj2mNAA=
+k8s.io/kube-openapi v0.0.0-20250710124328-f3f2b991d03b/go.mod h1:UZ2yyWbFTpuhSbFhv24aGNOdoRdJZgsIObGBUaYVsts=
 k8s.io/utils v0.0.0-20250820121507-0af2bda4dd1d h1:wAhiDyZ4Tdtt7e46e9M5ZSAJ/MnPGPs+Ki1gHw4w1R0=
 k8s.io/utils v0.0.0-20250820121507-0af2bda4dd1d/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
 sigs.k8s.io/json v0.0.0-20250730193827-2d320260d730 h1:IpInykpT6ceI+QxKBbEflcR5EXP7sU1kvOlxwZh5txg=
 sigs.k8s.io/json v0.0.0-20250730193827-2d320260d730/go.mod h1:mdzfpAEoE6DHQEN0uh9ZbOCuHbLK5wOm7dK4ctXE9Tg=
+sigs.k8s.io/kustomize/kyaml v0.21.0 h1:7mQAf3dUwf0wBerWJd8rXhVcnkk5Tvn/q91cGkaP6HQ=
+sigs.k8s.io/kustomize/kyaml v0.21.0/go.mod h1:hmxADesM3yUN2vbA5z1/YTBnzLJ1dajdqpQonwBL1FQ=
 sigs.k8s.io/randfill v1.0.0 h1:JfjMILfT8A6RbawdsK2JXGBR5AQVfd+9TbzrlneTyrU=
 sigs.k8s.io/randfill v1.0.0/go.mod h1:XeLlZ/jmk4i1HRopwe7/aU3H5n1zNUcX6TM94b3QxOY=
 sigs.k8s.io/structured-merge-diff/v6 v6.3.0 h1:jTijUJbW353oVOd9oTlifJqOGEkUw2jB/fXCbTiQEco=

matcher/glob.go

@@ -30,13 +30,26 @@ func asGlob(pattern string) (glob.Glob, error) {
 
 // splitSelector splits the given string into two pieces around an equal sign.
 func splitSelector(selector string) (string, string) {
-	parts := strings.SplitN(selector, "=", 2)
-	switch len(parts) {
-	case 2:
-		return parts[0], parts[1]
-	case 1:
-		return parts[0], ""
+	// Index for the last '=' and ']' characters. This is done as there are
+	// some selectors like '.spec.containers.[name=main].securityContext' and
+	// '.spec.containers.[name=main].image=docker.io/...' where blindly
+	// splitting on the first (or last) '=' character would be incorrect.
+	var (
+		indexEquals       = strings.LastIndex(selector, "=")
+		indexRightBracket = strings.LastIndex(selector, "]")
+	)
+
+	switch {
+	case indexRightBracket < indexEquals:
+		// The last '=' character exists after the last ']' character. Split on
+		// that index.
+		return selector[:indexEquals], selector[indexEquals+1:]
+	case indexEquals == -1:
+		// There is no '=' character. Return the input selector verbatim.
+		return selector, ""
 	default:
-		return "", ""
+		// There is no '=' character *after* a ']' character. Return the input
+		// selector verbatim.
+		return selector, ""
 	}
 }

matcher/matcher-fieldpath.go

@@ -0,0 +1,73 @@
+// Copyright Josh Komoroske. All rights reserved.
+// Use of this source code is governed by the MIT license,
+// a copy of which can be found in the LICENSE.txt file.
+// SPDX-License-Identifier: MIT
+
+package matcher
+
+import (
+	"fmt"
+
+	"github.com/gobwas/glob"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+
+	"github.com/joshdk/krf/resources"
+)
+
+// NewFieldPathMatcher matches resources.Resource instances that contain the given
+// Kustomize-style fieldpath, and optionally matching a target value at that
+// path.
+func NewFieldPathMatcher(selector string) (Matcher, error) {
+	path, value := splitSelector(selector)
+
+	m := fieldPathMatcher{fieldPath: path}
+
+	// No target value was given to match against, so we'll only be checking
+	// for the existence of the given fieldpath...path.
+	if value == "" {
+		return m, nil
+	}
+
+	valueGlob, err := glob.Compile(value)
+	if err != nil {
+		return nil, err
+	}
+
+	m.valueGlob = valueGlob
+
+	return m, nil
+}
+
+type fieldPathMatcher struct {
+	fieldPath string
+	valueGlob glob.Glob
+}
+
+func (m fieldPathMatcher) Matches(item resources.Resource) bool {
+	node, err := yaml.FromMap(item.Object)
+	if err != nil {
+		panic(err)
+	}
+
+	value, err := node.GetFieldValue(m.fieldPath)
+	if err != nil {
+		return false
+	}
+
+	// Return the existence of a matching fieldpath, since value matching was
+	// not requested.
+	if m.valueGlob == nil {
+		return true
+	}
+
+	switch value.(type) {
+	case string, int, bool, float64:
+		// Fieldpath evaluated to a simple type. Match the value glob against
+		// the stringified value.
+		if m.valueGlob.Match(fmt.Sprint(value)) {
+			return true
+		}
+	}
+
+	return false
+}

matcher/matcher-fieldpath_test.go

@@ -0,0 +1,54 @@
+// Copyright Josh Komoroske. All rights reserved.
+// Use of this source code is governed by the MIT license,
+// a copy of which can be found in the LICENSE.txt file.
+// SPDX-License-Identifier: MIT
+
+package matcher_test
+
+import (
+	"testing"
+
+	"github.com/joshdk/krf/matcher"
+)
+
+func TestFieldPathMatcher(t *testing.T) {
+	t.Parallel()
+
+	testMatcher(t, []spec{
+		{
+			title:   "compare value",
+			matcher: must(matcher.NewFieldPathMatcher(".spec.ports[0].port=80")),
+			matches: []string{"Service/my-service"},
+		},
+		{
+			title:   "compare null",
+			matcher: must(matcher.NewFieldPathMatcher(".spec.securityContext=null")),
+			matches: []string{"Pod/test-pod"},
+		},
+		{
+			title:   "nonexistent path",
+			matcher: must(matcher.NewFieldPathMatcher(".foo.bar")),
+			matches: []string{},
+		},
+		{
+			title:   "existence of path",
+			matcher: must(matcher.NewFieldPathMatcher(".data.username")),
+			matches: []string{"ConfigMap/my-configmap"},
+		},
+		{
+			title:   "wildcard value",
+			matcher: must(matcher.NewFieldPathMatcher(".data.username=*-admin")),
+			matches: []string{"ConfigMap/my-configmap"},
+		},
+		{
+			title:   "check for existence of a container with a specific name",
+			matcher: must(matcher.NewFieldPathMatcher(".spec.template.spec.containers.[name=nginx]")),
+			matches: []string{"Deployment/nginx-deployment"},
+		},
+		{
+			title:   "check for a specific volume mount",
+			matcher: must(matcher.NewFieldPathMatcher(".spec.containers.[name=test-container].volumeMounts.[name=config-volume].mountPath=/etc/conf*")),
+			matches: []string{"Pod/test-pod"},
+		},
+	})
+}