add possibility to exted behaviour of fmf by plugins with one for references

[jscotka]

userstory

• I want to use some template what is not directly in tree structure
• I want to construct testplan based on fmf metadata for components

with references:

• inherit from current tree
  $ PYTHONPATH=. python3 fmf/cli.py show --plugin reference --path examples/plugin_resolver/
• explict reference item by paht ( or pathes separated by :) (usecase is, to have fmf metadata eg in compoments and be able to construct testplan using testcases from component fmf metadata)
  PYTHONPATH="." python3 fmf/cli.py show --plugin=reference:examples/plugin_resolver/:examples/wget --path examples/plugin_resolver/

/a/b/c/leaf1
first: True
fourth: True
second: True
third: True
x: 4

/a/b/c/leaf2
first: True
second: True
third: True
x: 5

/d/dddd
filtered: asd
tags: a and b
y: 1

/inherited/tree@a/b/c/leaf1
first: True
fourth: True
inside: value
second: True
third: True
x: 4

/inherited/tree@a/b/c/leaf2
first: True
inside: value
second: True
third: True
x: 5

/inherited@dddd
filtered: asd
hallo: world
tags: a, b and c
y: 1

/referencedget@protocols/ftp
description: Test file download using the ftp protocol.
details: This is a very long and detailed description of what the wget/protocols/ftp test actually does including multiple examples and information about proper environment setup.
inside: value
tags: Tier1 and ref_inherited
test: runtest.sh
tester: Petr Šplíchal <psplicha@redhat.com>
time: 1 min

/referencedget@protocols/http
description: Test file download using the http protocol.
details: This is a very long and detailed description of what the wget/protocols/http test actually does including multiple examples and information about proper environment setup.
inside: value
tags: Tier1 and ref_inherited
test: runtest.sh
tester: Petr Šplíchal <psplicha@redhat.com>
time: 1 min

/referencedget@protocols/https
description: Test file download using the https protocol.
details: This is a very long and detailed description of what the wget/protocols/https test actually does including multiple examples and information about proper environment setup.
inside: value
tags: Tier1 and ref_inherited
test: runtest.sh
tester: Petr Šplíchal <psplicha@redhat.com>
time: 1 min

without references:

PYTHONPATH="." python3 fmf/cli.py show --path examples/plugin_resolver/

/a/b/c/leaf1
first: True
fourth: True
second: True
third: True
x: 4

/a/b/c/leaf2
first: True
second: True
third: True
x: 5

/d/dddd
filtered: asd
tags: a and b
y: 1

/inherited/tree@a
inside: value

/inherited@dddd
hallo: world
tags: c

/referencedget@protocols
inside: value
tags: ref_inherited

[coveralls]

Pull Request Test Coverage Report for Build 205

• 14 of 80 (17.5%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-11.4%) to 88.601%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
fmf/cli.py	6	21	28.57%
fmf/base.py	8	25	32.0%
fmf/plugins/reference.py	0	34	0.0%

Totals
Change from base Build 197:	-11.4%
Covered Lines:	513
Relevant Lines:	579

---

💛 - Coveralls